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DOE/ER-0601P

UC-402

Summaries of FY 1993

Engineering Research

September 1993

U.S. Department of Energy

Office of Energy Research

Office of Basic Energy Sciences

Division of Engineering and Geosciences

Washington, DC 20585
Foreword

This report documents the BES Engineering Research Program for fiscal year 1993; it

provides a summary for each of the program projects in addition to a brief program

overview. The report is intended to provide staff of Congressional committees, other

executive departments, and other DOE offices with substantive program information so as

to facilitate governmental overview and coordination of Federal research programs. Of

equal importance, its availability facilitates communication of program information to

interested research engineers and scientists. The organizational chart for the DOE Office

of Energy Research (OER) on the next page delineates the six Divisions within the OER

Office of Basic Energy Sciences (BES). Each BES Division administers basic, mission

oriented research programs in the area indicated by its title. The BES Engineering

Research Program is one such program; it is administered by the Engineering and

Geosciences Division of BES. Dr. Oscar P. Manley is technical manager of the

Engineering Research Program; inquiries concerning the program may be addressed to

him, in writing or by phone at (301) 903-5822.

In preparing this report we asked the principal investigators to submit summaries for their

projects that were specifically applicable to fiscal year 1993. The summaries received have

been edited if necessary, but the press for timely publication made it impractical to have

the investigators review and approve the summaries prior to publication. For more

information about a given project, it is suggested that the investigators be contacted

directly.
ENGINEERING RESEARCH PROGRAM WITHIN DOE

Secretary of Energy

Deputy Secretary

Under Secretary

' -- , I '

Assistant Secretaries Office of Energy Research * Federal Energy Regulatory

· Nuclear Energy Commission · Conservation and Renewable * Economic Regulatory · Fossil Commission · Defense * Energy Information · Environment, Safety 6 Health Administration · Environmental Restoration * International Affairs, etc.

I

Program Analysis Basic Enrgy Science Management Magnetic Fusion .* Special Programs High Energy and Nuclear Physics Scientific Computing Health and Environmental Research Science and Technology Advisor

Field Operations

· Material Sciences Division Engineering and * Advanced Energy Projects · Chemical Sciences Division Geosciences Division * Energy Biosciences

Engineering

Research Program
Introduction

The individual project summaries follow the program overview. The summaries are

ordered alphabetically by name of institution and so the table of contents lists all the

institutions at which projects were sponsored in fiscal year 1993.

The projects are numbered sequentially for individual identification in the indexes. Each

project entry begins with an institutional-departmental heading. The names of investigators

are listed immediately below the title. The funding level for fiscal year 1993 appears to

the right of title; it is followed by the budget activity number (e.g., 01-A). These numbers

categorize the projects for budgetary purposes and the categories are described in the

budget number index. The fiscal year in which either the project began or was renewed

and the anticipated duration in years are indicated respectively by the first two and last

digits of the sequence directly below the budget activity number (e.g., 90-3). The summary

description of the project completes the entry.
Program Review

BES Engineering Research

The BES Engineering Research Program is one of the component research programs which

collectively constitute the DOE Basic Energy Sciences Program. The DOE Basic Energy

Sciences program supports energy related research in the physical and biological sciences,

and in engineering. The chief purpose of the DOE Basic Energy Sciences Program is to

provide the fundamental scientific base on which identification and development of future,

national energy options will depend. The major product of the program becomes part of

the body of data and knowledge upon which the applied energy technologies are founded;

the product is knowledge relevant to energy exploration, production, conversion and use.

The BES Engineering Research Program was started in 1979 to help resolve the numerous

serious engineering issues arising from efforts to meet U.S. energy needs. The program

supports fundamental research on broad, generic topics in energy related engineering topics

not as narrowly scoped as those addressed by the shorter term engineering research projects

sponsored by the various DOE technology programs. Special emphasis is placed on

projects which, if successfully concluded, will benefit more than one energy technology.

During the first year several workshops were sponsored for the purpose of identifying

energy related engineering research needs and initial priorities. Representatives from

industry, academic institutions, national laboratories, and leading members of professional

organizations (Engineering Societies Commission of Energy, American Society of

Mechanical Engineers, Society of Automotive Engineers, and Joint Automation and Control

Committee) participated in the workshops. In addition to the participants in the workshops,

staff representatives from the DOE technology programs and other leading U.S. energy

engineering experts made significant contributions to the setting of program priorities.

There resulted from this process a strong confirmation of the need for a long range,

fundamental engineering research program with two major goals. The broad goals that

were established by this process for the BES Engineering Research Program are:

1) To extend the body of knowledge underlying current engineering practice so as to

create new options for enhancing energy savings and production, for prolonging useful

equipment life, and for reducing costs without degradation of industrial production and

performance quality; and

2) To broaden the technical and conceptual base for solving future engineering problems

in the energy technologies.
In this process, it was further established that to achieve these goals, the BES Engineering

Research Program should address the following topics identified as essential to the progress

of many energy technologies:

1) Advanced Industrial Technology: improvement of energy conversion and utilization,

opening new technological possibilities, and improvement of energy systems.

2) Fluid Dynamics and Thermal Processes: broadening of understanding of heat transfer

in nonsteady flows, methodology for reducing vibrations and noise in heat exchangers, and

engineering aspects of combustion.

3) Solid Mechanics: continuum mechanics, fracture mechanics, thermomechanical

behavior in severe environments, aging & lifetime reliability of structures.

4) Dynamics and Control of Processes and Systems: development and use of information

describing system behavior (system models), performance criteria, and theories of control

optimization to achieve the best possible system performance subject to known constraints.

A Scoping Workshop held in December, 1985 confirmed the continued needs for research

in these topical areas. Because of budgetary limitations, the implemented BES Engineering

Research Program is somewhat less broad than the program envisioned above. At present,

equal emphasis is being placed in three carefully selected, high priority research areas;

namely,

1) Mechanical Sciences including fluid mechanics (multiphase flow and turbulence) heat

transfer, and solid mechanics (continuum mechanics and fracture mechanics).

2) System Sciences including process control and instrumentation.

3) Engineering Analysis including nonlinear dynamics, data bases for thermophysical

properties of fluids, modeling of combustion processes for engineering application, and

foundations of bioprocessing of fuels and energy related wastes.

These areas contain the most critical elements of the four topics enumerated above; as such

they are of importance to energy technologies both in the short and long term, and

therefore of immediate programmatic interest. It should be noted that other areas of basic

research important to engineering are monitored elsewhere in BES. For instance,

separation sciences and research on thermophysical properties are among the

responsibilities of the Chemical Sciences Division, while microscopic aspects of fracture

mechanics are in the domain of the Material Sciences Division. As resources permit, other

high priority areas are being added to the Engineering Research Program. Thus, as a result

of previous growth in the program budget an important development took place in the

Engineering Research Program: two major concentrations of research were initiated.
First, a new program was organized at Oak Ridge National Lab dealing with intelligent

machines in an unstructured environment. Some resources are available for coordinated,

more narrowly focussed, related, high quality research at universities and other research

centers. All such activities are supported and administered directly by the Engineering

Research Program, but some coordination of efforts with the ORNL program may prove

useful.

Secondly in FY 1985, a collaborative research effort was started between MIT and Idaho

National Engineering Lab. At present, the collaboration is in three distinct areas: Plasma

Process Engineering, Automated Welding, and Fracture Mechanics. Collateral, high quality

research efforts at other institutions are supported by the Engineering Research Program.

In the expectation of a future modest growth of this Program, two International Workshops

on Two Phase Flow Fundamental were held one in September 1985 and the other in

March, 1987. The meetings were used to identify basic research needs in the field of two

phase flow and heat transfer; summary reports of the workshops are available from the

Program Office. The proceedings of the two workshops have been published as volumes

in the series "Advances in Heat and Mass Transfer" (Hemisphere Publishing Company).

A third international workshop held in June 1992 surveyed the status of the field. The

proceedings will be published by CRC Publishing Company.

Two additional workshops were held during 1988. The first dealt with possible research

opportunities in the field of novel devices using the new high temperature superconductors.

The second addressed research needs for bioprocessing of fuels and energy related wastes.

Reports of both workshops have been published. Additional funds have been provided in

FY 1992 to initiate research in the above mentioned bioprocessing area. Of interest are

relevant studies at the intersection of biology, biochemistry, and chemical engineering.

Another workshop aimed at identifying research opportunities to mitigate the effects of

aging in energy production and distribution systems took place in October 1992. The

proceedings have appeared in Applied Mechanics Reviews.

It should be mentioned too, that some very limited support is available for research on

large scale systems. A report of a workshop on needs, opportunities, and options in this

field is available from Professor G.L. Thompson, Graduate School of Industrial

Administration, Carnegie-Mellon University, Pittsburgh, PA 15213. Also there is some

interest in addressing the basic foundations of advanced manufacturing processes. In this

context 24 three-year doctoral fellowships administered by National Academy of Science

and National Research Council have been sponsored.

Research projects sponsored by the BES Engineering Research Program are currently

underway at universities, private sector laboratories, and DOE national laboratories. In

fiscal year 1993 the available program operating funds available amounted to about $16.2

million. The distribution of these funds among various institutions and by topical area is
illustrated on the next page. Project funding levels are mostly in the range of $50,000 to

$150,000 per year. Typical duration of a project is three to four years, with some projects

expected to last as long as ten years or more. The BES Engineering Research projects

stem almost without exception from grant applications. Applications which anticipate

definite results in less than two years are usually referred to the appropriate DOE

technology program for consideration. All those interested in submitting a proposal are

encouraged to discuss their ideas with the technical program manager prior to submission

of a formal proposal. Such discussion helps to establish whether or not a potential project

has a reasonable chance of being funded. The primary considerations for possible support

are the technical quality of the proposal and the professional standing of the principal

investigators and staff. An effort is made to attract first rate, younger research engineers

and energy oriented applied scientists. A high technical caliber of research is maintained

by requiring that the projects supported have potential for a significant contribution to

energy related engineering science, or for an initial contribution to a new energy relevant

technology. Sponsored projects are selected primarily for their relevance to DOE mission

requirements; the contribution to energy related graduate education is an important

consideration. Thus projects sponsored at universities are essentially limited to advanced

theoretical and experimental studies usually performed by faculty members, staff research

scientists, and doctoral candidates.
ENGINEERING RESEARCH PROGRAM

FY '93 BUDGET ($000's)

BY INSTITUTIONAL TYPE

NATIO NAL

LABORATORIES

27.3% \ UNIVERSITIES

$4420 62.4%

(17 Projects) n $10103

(93 Projects)

OTHER

10.3%

$1678

(10 Projects)

ENGINEERING RESEARCH PROGRAM

FY'93 BUDGET

BY TECHNICAL AREAS

($000's) % NUMBER OF PROJECTS

MECHANICAL SCIENCES 5329 32.9 51

SYSTEMS SCIENCES 4573 28.2 22

ENGINEERING ANALYSIS 6300 38.9 47
Table of Contents

University of Alabama ................................ 1

Argonne National Laboratory ................... 1.....

University of Arizona .............................. ... 2

Arizona State University ............................ ... 3

Battelle Memorial Institute ............. ........ ....... 3

University Of California, Berkeley ........................ 4

University Of California, Los Angeles ..................... 5

University Of California, San Diego ....................... 6

University Of California, Santa Barbara . ................... 9

California Institute Of Technology ................... ..... 10

Carnegie Mellon University ............................ 10

University Of Chicago ................................. 12

Clarkson University .................................. 13

University Of Connecticut .............................. 13

Cornell University ................................... 14

Dartmouth College ................................... 15

Duke University .................................... 16

Engineering Science Software, Inc .. ...................... 13

Idaho National Engineering Laboratory .......... ........ 16

University Of Illinois ................................. 19

University Of Illinois At Chicago ........................ 20

Johns Hopkins University .............................. 21

Robert H. Kraichnan, Inc ............................... 21

Lawrence Berkeley Laboratory .......................... 22

Lovelace Medical Foundation ........................... 22

University Of Maryland .... ................ ......... 22

University Of Massachusetts ........ ............ ...... 25

University Of Massachusetts-Lowell .................. .... 25

Massachusetts Institute Of Technology . .................... 26

University Of Minnesota .............................. 29

National Academy of Sciences/National Research Council ....... 30

National Center for Manufacturing Sciences ................. 31

National Institute Of Standards And Technology .............. 31

The City University Of New York, The City College .. ......... 32

Northwestern University . .............................. 33

University Of Notre Dame ............................. 35

Oak Ridge National Laboratory .......................... 36

Ohio State University ................................. 36

Oregon State University ............................... 37
Table of Contents (continued)

Pacific Northwest Laboratory .......................... 38

University Of Pennsylvania ......................... 38

Pennsylvania State University .......................... 39

Physical Sciences Inc ................................ 39

Princeton University ...................... ...... 40

Purdue University ....................... .... 41

Rensselaer Polytechnic Institute .......................... 42

Rice University ........................ ...... 43

University Of Rochester ............................. 44

Rockefeller University ................................ 45

Sandia National Laboratories .......................... 45

University Of Southern California ........................ 46

Southwest Research Institute ......................... 47

Stanford University .. ............... ......... 48

Stevens Institute Of Technology ......................... 51

Texas A&M University ............................... 52

University Of Texas At Austin ..................... .. 52

Tufts University ........................... 53

United Technologies Research Center ...................... 53

Washington University ............................ 54

Washington State University .......................... 54

University Of Wisconsin .............. .............. 55
University Of Alabama Argonne National Laboratory

Dept of Mathematics $54,123 Energy Technology Division $134,000

Tuscaloosa, AL 35487 01-C Argonne, IL 60439 01-A

91-3 90-3

Hydrodynamic Instabilities and Coherent Chaos in Fluid-Structure Systems

Structures S. Chen

A. Frenkel

Energy systems have had a history of dynamic

The objective of this research is to further the structural instabilities caused by fluid flow resulting

fundamental understanding of stability properties in costly component repair and replacement and

of several far-from-equilibrium fluid systems which loss of energy production. Integrated theoretical

are relevant to energy engineering sciences. In and experimental studies are being performed to

particular, flows periodic in space and possibly in enhance the understanding of nonlinear

time are studied as models to gain insights into oscillations and dynamic instability phenomena

such turbulence phenomena as large-scale involving both fluids and solid structures and their

coherent structures, eddy viscosity, and the coupling. The objectives are to contribute to the

inverse cascade of energy. Film flows - such as explanation of observed phenomena, providing

core-annular ones - are important to, e.g., insights into chaotic characteristics of such

lubricated pipelining of viscous oils. The coupled mechanical systems and ultimately, to the

large-scale evolution equations for the different solution of engineering design problems. This is

systems may exhibit common features, such as a cooperative research program with Professor F.

pattern formation and coherent structures. Moon at Cornell University.

Secondary instabilities of nonlinear waves in liquid

films can be studied with methods developed for Fluidelastic instability of loosely supported tubes,

periodic flows. vibrating in a tube support plate-inactive mode, is

suspected to be one of the main causes of tube

Some of the results are as follows: A rigorous failure in some operating steam generators and

iterative method was found for the problems of heat exchangers. As a vehicle to understand the

periodic-flow stability. The possibility of negative nonlinear behavior of fluid-structure systems,

isotropic eddy viscosity was demonstrated, fluidelastic instability of loosely supported tube

resolving a rather long-outstanding question. arrays in crossflow is being studied in detail. A

series of tube arrays with a motion-limiting stop

For film flows, a perturbative method capable of configuration are being tested to investigate

yielding both the evolution descriptions and the various response characteristics and a

parametric conditions of their validity was mathematical model based on the unsteady flow

suggested. A highly nonlinear evolution equation theory has been developed to predict the response

for large-amplitude regimes of a wavy flow was characteristics of this classical fluid-structure

obtained. Its numerical simulations yielded an system. Other fluid-structure systems, such as

excellent agreement with experiments. In addition, coupled stack/wire dynamics due to wind

it revealed interacting coherent structures with rich excitations, are also being investigated. Analytical

and unique dynamics. results and experimental data agree fairly well.

Some fundamental questions concerning Tests and analysis of tube arrays are being

commonly used perturbative approaches were continued. One of the key elements is the motionclarified. Certain deficiencies of well-known dependent fluid forces which will be measured

evolution equations were pointed out. using the existing water channel with an emphasis

on the nonlinear behavior. Specific topics to be

addressed include interaction between flow field

and oscillating structures, mathematical models

and instability mechanisms, and intelligent control

of fluid/structure systems. Experimental efforts are

focused on characterizing and controlling chaos.

and validating analytical models.

Engineering Research 1 1993
Argonne National Laboratory University of Arizona

Reactor Engineering Division $137,000 Aerospace & Mechanical Eng $136,301

Argonne, IL 60439 01-A Tucson, AZ 85721 01-B

90-3 93-3

Bounds on Dynamic Plastic Deformation Film Cooling in a Pulsating Stream

C. Youngdahl I. Wygnanski

Analytical studies are being performed to develop This project will deal with heat transfer to or from

methods for approximating or bounding the an isothermal surface whose temperature will be

dynamic plastic deformation of structures. In either hotter or colder than the jet temperature.

many applications where the load is transmitted to The jet temperature, on the other hand, might be

the structure through a fluid, details of the load equal to or different from the ambient temperature.

history and spatial distribution significantly affect This will help us to separate the coherent

the final plastic deformation. The objective of the structures which are affected by the heat flux from

program is to devise mode approximation methods the surface from the coherent structures which are

and load correlation parameters which can be affected by the heat flux occurring between the jet

used to predict the final deformed shape and and the ambient stream (i.e. in the outer mixing

characterize the effects of the load without layer). The wall jet will flow over a thick

resorting to detailed numerical analyses. These conducting plate placed above a constant

approximation methods have three important uses: temperature reservoir which might be either hotter

to perform design and safety analyses of or colder than either the jet or the ambient fluid.

structures over a wide range of design variables Measurements of turbulent heat flux in the

and loadings; to validate computer programs which direction normal to the plate will be accomplished

have a nonlinear dynamic plasticity capability. and with a combination of hot-wire anemometers and

to correlate experimental simulations with actual or miniature thermocouple sensors (effective

predicted events. diameters 0.003 in.), or by a combination of coldwire (resistance) anemometers and PIV (Particle

Mode approximation methods and load correlation Image Velocimeter).

parameters are hypothesized and their usefulness

in predicting final plastic deformation is We shall start the study with the unheated jet

determined. Optimum modes have been flowing over a heated surface thus the flow will

determined for the dynamic plastic deformation of never attain a thermal equilibrium with the surface.

simply-supported, clamped, and cantilevered Whenever the wall and the ambient stream are at

beams made of a rigid, strain hardening material. the same temperature but the jet emerges from

The modes are expressed in terms of amplitude the nozzle at a different temperature the flow

and plastic zone size functions which are might approach an equilibrium fardownstream due

determined for arbitrary loadings by the numerical to the finite heat flux from the nozzle. We propose

solution of sets of coupled, non-linear differential to initiate an investigation in the absence of an

equations. Computational times are of the order external stream and we shall add a relatively weak

of seconds rather than the hours usually spent on external stream soon thereafter. Forcing the flow

dynamic plasticity problems. uniformly across the span at a single frequency

will provide a well-defined correlation between the

large spanwise eddies and heat transfer.

Engineering Research 2 1993
The first step in each investigation will cover the Another task was to determine the scaling law for

Reynolds averaged quantities for the unperturbed the effective stiffness of a two-dimensional

flow. This will include temperature ranges which continuum weakened by a random distribution of

will alter the mean flow characteristics through the rectilinear slits. The solution was derived (within

nonlinear coupling between velocity and the node-link-blob model) for the elastic and

temperature fluctuations while keeping the elasto-plastic materials using the exact stress

boundary conditions at the wall and at infinity well fields at the crack tip. A rather careful search of

defined (i.e. constant). It will enable us to validate the literature indicates this to be the first solution

our experimental techniques and our numerical for the elasto-plastic solid.

codes as well as some of the conventional models

used. We may also consider the major instability

mechanisms of such flows in order to establish the Battelle Memorial Institute

forcing parameters needed as inputs to the second Engineering Mechanics Dept $94,027

stage (the main stage) of the investigation. It will Columbus, OH 43201-2693 01-A

be useful to consider the relative significance of 90-3

the secondary instabilities and the non planar An Investigation of History Dependent

modes as their relevance may be altered by the Damage In Time Dependent Fracture

addition of heat. (We only recently discovered that Mechanics

the plain, unforced, turbulent incompressible wall- F. Brust, Jr.

jet contains two, nonlinearly coupled modes of

instability. Both must be considered in any The goal of this research is to study the highattempts to understand and control the wall jet) temperature damage and failure processes and to

We will then force the flow by providing velocity further develop a method for predicting this

oscillations emanating from the plenum chamber behavior in an effort to increase structural life. In

and later we may attempt to force the flow by particular, we focus on time-dependent damage

using oscillatory heating thus altering the forcing which occurs under history-dependent loading

between velocity and temperature fluctuations. conditions, i.e. transient conditions.

The approach taken here is to combine

Arizona State University experimental studies of both sustained-load and

Mechanical & Aerospace Eng $50,000 variable-load creep with careful analytical studies.

Tempe, AZ 85287 01-A To date, eight crack-growth tests on both a

92-4 stainless steel and a 9CRMo steel have been

Contiuum Damage Mechanics - Critical States performed. These time dependent crack-growth

D. Krajcinovic specimens were subjected to carefully chosen

load-history spectrums so that different crackThe objective of this research project is to growth histories were obtained. The implications determine the critical states of brittle solids of using classical creep constitutive theories

weakened by a large number of microcracks. This (Norton, strain hardening) to predict the behavior

objective is pursued using the methods of applied were ascertained. In addition, the use of various

mechanics, thermodynamics and statistical integral parameters to characterize the crack tip

physics. The thermodynamic studies of the loose phenomena were developed and evaluated.

bundle parallel bar model were used to define

possible expressions for damage variables and It was clearly shown that constitutive laws such as

conjugate forces. The failure criterion was derived Murakami-Ohno Krempl-type laws must be used in

in form of a generalized Griffith's criterion. A order to adequately predict the response. Most

distinction was made between the force controlled importantly, recently it has been shown that new

processes, in which the failure is a second order energy-based integral parameters can characterize

phase transition, and the displacement controlled the crack- growth behavior of the test specimens

processes. Universal character of scaling laws subjected to complex history-dependent loading.

and percolation thresholds is guaranteed only in In addition, they can predict crack nucleation.

the first case. Classical methods based upon rate-type

asymptotic parameters developed from simple

constitutive theories break down.

Engineering Research 3 1993
University Of California/B University Of California/B

Dept of Electrical Engineering $184,369 Dept of Mechanical Engineering $120,603

& Computer Sciences 06-C Berkeley, CA 94720 01-B

Berkeley, CA 94720 93-3 92-3

Thermal Radiation and Conduction in

Dynamics of Electronegative Plasmas for Microscale Structures

Materials Processing C.-L. Tien

A. Lichtenberg, M. Lieberman

The general objective of this research program is

The purpose of this project is to study electron to achieve a better understanding of the

heating mechanisms in radio frequency (r.f.) fundamental mechanisms of thermal radiation and

discharges. These discharges are used heat conduction in microscale structures

extensively by industry for surface modification of commonly encountered in engineering

electronic and mechanical materials. In addition to applications. Specifically, the program includes

the usual r.f. ohmic heating in the plasma interior, investigations of radiative heat transfer in thin

it has been found theoretically that stochastic films, conductive heat transfer in quantum well

heating at the plasma surface arising from laser, and short-pulse laser-material interactions.

successive decorrelated reflections of electrons

with the oscillating sheath plays a major role. The A combined analytical and experimental research

efficiency of stochastic heating depends on the program on radiative interactions with

detailed sheath dynamics. microstructures has been directed to characterize

(1) the partially coherent radiative properties of

The sheath dynamics have been measured and thin films and (2) the strong coupling between

related to the predicted stochastic heating for a electromagnetic wave propagation and the

plane parallel argon discharge. The measured radiation absorption thermal field. The findings are

results, together with related plasma simulations, useful for optical characterization of thin films,

have been used to construct better predictive design and operation of optical bistability devices,

models of discharge behavior and parameter and localized processing of film structures.

scaling. It has been found for a low pressure

discharge at 3 mTorr, power of 100 watts, and Allium arsenide based quantum well lasers

frequency of 13 MHz,95% of the electron heating represent a rapidly expanding area of research

is predicted to occur stochastically. and development. A new measurement technique

that determines thermal diffusion of thin films in

Stochastic heating can be enhanced with a both parallel and perpendicular directions has

resonant helical discharge structure. This been developed, and the experimental results

geometry is of importance for materials processing agree with those of the concurrent theoretical

applications in that it may be operable at very low study. With knowledge of the anisotropic thermal

pressure (<1 mTorr). Studies of stochastic heating diffusivity in semiconducting quantum well lasers,

and determination of equilibrium plasma the temperature rise and heat generation

parameters have been made in argon and mechanisms at the facets were further

nitrogen, with good agreement between theory and investigated.

experiment.

Pulse durations in modem short-pulse lasers have

been reduced from microseconds to

femtoseconds, greatly increasing the time

resolution of optical observations and the spatial

controllability of laser processing. A general

macroscopic model based on microscopic

electron-lattice interaction and electron transport

was developed to describe short-pulse laser

heating of metals. Femtosecond laser heating

experiments were conducted for single and multilayer metal films. The knowledge gained in this

research program is useful for the thermal design

Engineering Research 4 1993
of high-power laser components and for a better University Of CaliforniaLA

control of short-pulse laser microfabrication as well Mech, Aero & Nuclear Eng ept $112,850

as short-pulse laser diagnostics. School of Eng & Applied Science 06-C

Los Angeles, CA 90024 93-3

University Of California/LA Linear Kinetic Theory and Particle

Mech, Aero & Nuclear Eng Dept $90,024 Transport in Stochastic Mixtures

School of Eng & Applied Science 01-C G. Pomraning

Los Angeles, CA 90024-1597 92-3

The goal in this research is to develop a

Basic Studies of Transport Processes in comprehensive theory of linear transport/kinetic

Porous Media theory in a stochastic mixture of solids and

I. Catton, V. Travkin, L. Gratton immiscible fluids. Such a theory should predict the

ensemble average and higher moments, such as

The research seeks to develop the methods the variance, of the particle or energy density

necessary to model turbulent transport processes described by the underlying transport/kinetic

for both single- and two-phase flows in highly equation. The statistics to be studied correspond

porous media. Emphasis is placed upon the to N-state discrete random variables for the

development and theoretical study of interaction coefficients and sources, with N

integro-differential transport equations, with special denoting the number of components in the

attention given to morphological factors. Research mixture. The mixing statistics to be considered

has focused upon (1) single-phase, two- are Markovian as well as more general statistics.

temperature turbulent transport in porous media,

and (2) turbulent transport of momentum and In the absence of time dependence and scattering,

energy in a channel with regular rough walls. the theory is well developed and described by the

master (Liouville) equation for Markovian mixing,

Dependence of the Darcy and quadratic terms and by renewal equations for non-Markovian

upon the convective and diffusion terms' assumed mixing. The intent of further work is to generalize

version has been shown, as has the connection these treatments to include both time dependence

between the diffusion and drag resistance terms in and scattering. A further goal of this research is to

the flow equations. The closure models allowed develop approximate, but simpler, models from the

associations between bulk process experimental comprehensive theory. In particular, a specific

correlations and the current simulation goal is to formulate a renormalized transport/

representations to be exploited in the numerical kinetic theory of the usual nonstochastic form, but

procedures. Subsequent numerical investigations with effective interaction coefficients and sources

displayed the equations' sensitivity to the assumed to account for the stochastic nature of the

morphology and the transport coefficients' problem. Numerical comparisons of all models will

descriptive ability for high solid/fluid phase thermal be made against Monte Carlo simulations which

diffusivity ratios and high void fractions. involve a straightforward average of solutions for

a large number of physical realizations of the

Two-dimensional capillary patterns and spherical statistical mixing. Contact will also be made with

structures were analyzed using an irregular four- experimental simulations of cloud-radiation

coordinate lattice with varying bond orientations interactions currently underway at another

and random lattice patterns. Prescription of the institution as part of DOE's global climate

medium's statistical structure allowed modeling initiative.

transformation of the integro-differential transport

equations into differential equations with probability

density functions governing the spatially varying

stochastic coefficients and source terms.

Combination of space averaging and random

morphology process theories resulted in realistic

explanation of processes in porous media.

Engineering Research 5 1993
University Of California/LA of unfolding the attractor using the method of

Physics Dept $79,000 global false nearest neighbors and then

Los Angeles, CA 90024 06-C determining locally the number of dynamical

93-3 degrees of freedom using the local version of this

Nonlinear Waves in Continuous Media has brought to the study of complex behavior a

S. Putterman robustness which allows it to be used in

engineering analysis and design. The algorithms

Nonlinear wave interactions in far off equilibrium developed for this purpose have also been used in

fluids are being studied with the goal of a variety of applications requiring the separation of

understanding the interplay between processes a chaotic signal from another information bearing

that, concentrate energy (e.g. sonoluminescence), signal or 'noise'. The tool kit of these algorithms

randomize energy (e.g. wave turbulence) and is being ported to a common interface for use in

form localized states (e.g. solitons). The the energy related sciences.

experimental discovery that strong sound waves

generate picosecond flashes of light is now being

studied from the theoretical perspective with the University Of California/SD

goal of understanding how energy can focus by Dept of App Mech & Eng Sci $126,000

twelve orders of magnitude. Turbulence in La Jolla, CA 92093 06-B

nonlinear waves is being studied from both the 93-3

theoretical and experimental directions. Goals Fundamental Studies of Spray Combustion

include the development of a Fokker-Planck theory P. Libby, F. Williams

that includes intermittency as well as the

observation of collective modes in turbulence that This research involves a combined experimental

are analogous to second sound. High amplitude and theoretical effort related to the behavior of fuel

waves can also form self-localized states such as droplets in well defined but nonuniform flows. Our

the breather and kink solitons, and domain walls current research concerns fuel sprays in opposed

which have recently been observed. Current and impinging streams which result in flat flames.

efforts are aimed at extending these findings to A test rig which permits a wide variety of

systems which are two and three dimensional. investigations including nonpremixed, premixed

This work proceeds from the experimental, and partially premixed systems in opposed and

analytical and simulational avenues of approach. impinging flows has been put into operation. By

installing an appropriate grid in one or both ducts

sprays in turbulent streams can be studied. Initial

University of California/SD results involve the structure and extinction

Scripps Inst of Oceanography $165,000 characteristics of laminar flames using a phase

La Jolla, CA 92093-0402 06-C doppler particle analyzer which permits

90 4 measurement of two velocity components, droplet

Nonperiodic, Broadband Signals: diameter and number density. Several

Signal Processing in Chaos publications on this research have appeared. One

H. Abarbanel interesting observation from these laminar studies

is that under some flow conditions larger droplets

The analysis of chaotic signals observed in from the spray pass through the stagnation plane

measurements on physical systems is of into the opposing gas stream and oscillate about

importance in energy problems ranging from that plane. This phenomenon has been studied

fluidized bed flows in fossil energy applications to experimentally in terms of single droplets and in

determination of the natural climate variability to sprays. Related theoretical studies identify the

the uncovering of simple models for complex parameters of droplet and flow determining

behavior in fluid flows. This research has whether or not oscillations occur. An interesting

developed tools for this analysis which allows one manifestation of such oscillations in sprays is that

to reconstruct the multivariate state space of a the probability density of the axial velocity of

system from observations, time lagged, of a single droplets on the axis of the flow at points above the

dynamical variable. The time delay, the stagnation plane can be bimodal with both positive

dimension, and properties of the strange attractor and negative velocities. A theoretical treatment of

can all be determined from this data. The concept this phenomenon is underway. Initial experiments

Engineering Research 6 1993
on a turbulent spray impinging on a wall without University Of California/SD

combustion with the aim of determining the relative Department of Mathematics $98,000

velocity between gas and droplets of various sizes La Jolla CA 92093 06-C

has been completed. Data analysis and 93-1

interpretation are underway. -Knot Invariants and the Thermodynamics

of Lattice Gas Automata

D. Meyer University Of California/SD

Department of Chemistry, 0340 $183,512 Some discrete models for dynamical systems (like

La Jolla, CA 92093 06-C lattice gas hydrodynamics) exhibit approximately

92-4 thermodynamic behavior despite the presence of

Noisy Nonlinear Systems conserved quantities other than the energy/

K. Lindenberg momenta and even for small system size (e.g., the

lattice gas models for two phase flow through

The broad objective of this project is to investigate porous media). The goal of this project is to build

the interplay of nonlinear deterministic dynamics on the understanding of the connections between

with spatial and temporal fluctuations. knot invariants, exactly solvable statistical

mechanics models and discrete dynamical

Density fluctuations in binary reaction--diffusion systems gained in earlier work (appearing in

processes in low dimensional systems lead to Physica D and Knots 90) toward an answer to the

spatial and temporal anomalies. The asymptotic question of how this early and robust

behavior is well established, but sets in only after thermodynamic behavior occurs in lattice gas

extremely long times. The hierarchy of kinetic automata.

regimes for all times has now been determined

under a variety of conditions. This work continues The basis of the approach is exemplified by the

with a broader set of reactions and geometries. result that one specific reversible cellular

automaton model with a conserved quantity is

Transport on certain quasi-random fractals has equivalent, in the sense that the ensemble of 1 + 1

been determined analytically. One aim is to dimensional spacetime evolutions is the same as

extend the approach to more complex fractals. the equilibrium ensemble of 2 dimensional

Another is to investigate transport on structures configurations, to a solvable statistical mechanics

that in one extreme parameter regime are model at a critical point. In addition to the

Euclidean but in another are fractal. This is done association between the critical limit of solvable

by replacing holes or disallowed pathways on models and knot invariants, the physical

fractals with appropriate barriers. At short times a characteristics of the critical point are consistent

walk on such a structure is indistinguishable from with the canonical distribution observed in

that on the associated fractal; at long times it simulations.

should appear Euclidean. The crossover time

should be determined by a tunable parameter Current work includes the application of this

such as the temperature. Preliminary results approach to a family of 1 dimensional lattice gas

have been obtained. automata based on a model of 't Hooft. The

intention is also to study the relation between the

Systems subject to deterministic and/or stochastic lattice gas analysis of this model and 't Hooft's

forces exhibit interesting behavior caused by the defect/curvature interpretation. Recent

interplay of nonlinearity, noise and deterministic developments (Vassiliev knot invariants) are

forces. A path integral approach has been suc- expected to lead to a better understanding of the

cessful for the analysis of the response of non- connection between the usual perturbative

linear systems to colored noise; developments in analysis and global topological properties of these

this area continue. A difference equation approach nonlinear systems. Investigation of higher

has provided the response of a linear system to a dimensional models, via solutions of the

coin-toss square wave, leading to unexpected tetrahedron equation, has also begun.

non-monotonic response. The response of

nonlinear systems to combinations of deterministic

and stochastic forces is under investigation.

Engineering Research 7 1993
University Of California/SD University Of California/SD

Inst for Nonlinear Science, R-002 $95,145 Dept of Physics $219,120

La Jolla, CA 92093 06-C La Jolla, CA 92093 06-C

93-3 93-3

Structure of Turbulence, Conditional Traveling-Wave Convection in Fluid Mixtures

Averaging and Subgrid-Scale Modeling C. Surko

E. Novikov

This research program involves the study of

The direct numerical simulations (DNS) of convection in fluid mixtures of ethanol and water,

turbulent flows with high Reynolds numbers (which in which the fluid motion takes the form of

are encountered in many engineering enterprises), traveling waves. This is a model system for

are impossible now and in the foreseeable future. studying nonequilibrium, traveling-wave

The major goal of this project is to advance the phenomena that can provide important insights

knowledge of the structure of turbulence, aiming it into the behavior of doubly diffusive systems in

at a subgrid-scale modelling for the large-eddy which the transport occurs on two different time

simulations (LES). Among the tools being scales. In this system, the coupling of the

developed for achievement of this goal are: 1) concentration field to the velocity and temperature

conditional averaging of Navier-Stokes (NS) fields results in a wife variety of potentially

equations; 2) use of Markov processes with important phenomena. Examples of practical

dependent increments, consistent with NS interest include solar ponds and atmospheric and

equations, 3) description of intermittency in terms oceanographic flows.

of breakdown coefficients and associated infinitely

divisible probability distributions; and 4) Experiments involving an annular geometry have

incorporation of experimentally observed coherent been used to confine the convective rolls to a

structures into the statistical description of quasi one-dimensional pattern which facilitates a

turbulence. simplified theoretical analysis. As a result of this

work, there is now a basic understanding of the

A number of new results was obtained by using dynamics of uniform and confined states of

these tools, in particular, probability distribution for traveling waves, including an understanding of the

three-dimensional vectors of velocity increments, role that the concentration field plays in these

which has an unusual form. A hierarchy of dynamics. Recent work in this one-dimensional

subgrid-scale models was obtained and geometry bs focused on the instability of uniform

preliminary testing was done by DNS (for traveling waves to wavelength perturbations (i.e.,

moderate Reynolds numbers) and by LES for the "Eckhaus" instability). Experiments in progress

isotropic, shear-flow and free-surface turbulence. focus on the nature of traveling-wave convection

Numerical simulations are performed in in a large aspect ratio, two-dimensional geometry.

cooperation with workers at Stanford University Important issues to be addressed include twoand Science Applications International dimensional wavelength instabilities and the

Corporation. Corresponding laboratory dynamics of defects.

experiments (in particular, for free-surface

turbulence) are performed in cooperation with

Caltech. The obtained analytical, numerical and

experimental results open a new perspective for

more detailed studies of the structure of turbulence

and subgrid-scale modelling.

Engineering Research 8 1993
University Of California/SB We have continued our work on binary-mixture

Dept of Physics $264,290 convection. For positive separation ratios ' we

Santa Barbara, CA 93106 06-C studied square patterns. For negative f, we

93-5 investigated time formation of localized pulses in

Bifurcations and Patterns in Nonlineartwo dimensions.

Dissipative Systems

G. Ahlers, D. Cannell University Of California/SB

This project consists of experimental investigations Dept of Chemical & Nuc Eng $106,300

of heat transport, pattern formation, and bifurcation Santa Barbara, CA 93106 01-C

phenomena in non-linear non-equilibrium fluid- 91-3

mechanical systems. These issues are studies in Turbulence Structure and Transport

Rayleigh-Benard convection, using both pure and Processes in Wavy Liquid Streams

multicomponent fluids. They are of fundamental S. Banerjee, G. Hetsroni

scientific interest, but also play an important role in

engineering, materials science, ecology Experiments have been completed to visualize

meteorology, geophysics, and astrophysics. For wave turbulence interactions near shear-free gasinstance, various forms of convection are liquid interfaces. Mechanically generated waves of

important in such diverse phenomena as crystal different lengths and amplitudes were imposed on

growth from a melt with or without impurities, the flow and the effects on the turbulence structure

energy production in solar ponds, flow in the determined. It was found that the nearwall

earth's mantle geo-thermal stratifications, and structure was affected by interfacial waves in the

various oceanographic and atmospheric relatively shallow stream studied. In particular, the

phenomena. Our work utilizes computer- wall region was found to couple with waves in

enhanced shadowgraph imaging of flow patterns frequency ranges of about the same magnitude as

and high-resolution heat transport measurements. bursts/ejections. A paper has been published in

Physics of Fluids ("Wave-Turbulence Interactions

We studied convection in a gas (CO2) under in Free-Surf ace Channel Flows", M. Rashidi, G.

pressure (about 30 bar) in a very large aspect Hetsroni and S. Banerjee, 1992).

ratio sample (radius/height = 150). Under nonBoussinesq conditions, the bifurcation from In addition, work using laser Doppler anemometry

conduction to convection became hysteretic, and has continued in parallel with flow visualization. It

the initial pattern consisted of a perfect lattice has been found that wall region coherent

containing more than 104 hexagonal cells. For structures, which are normally thought of as

parameter values where time-independent parallel streaks, burst/ejections and in-sweeps, as well as

straight rolls were theoretically predicted for a relatively short quasi-streamwise vortices, may

laterally infinite system, we found a state of spiral- actually be one funnel-shaped structure in which

defect chaos. the fluid motion is initially in the form of relatively

tight quasi-streamwise vortices, later on expanding

We investigated convection in a nematic liquid to trace the surface of a funnel laid sideways in

crystal in a horizontal magnetic field H. We found the flow. The phenomenon, to some extent, is

excellent agreement with recent theoretical reminiscent of vortex breakdown. Ejections and

predictions for the bifurcation line R,(H), and for in-sweeps are then the rising and falling portions

the convection-roll orientations as a function of H. of fluid that trace the surface of the funnel. Work

We also used this system to study convection is continuing to establish whether these are in

when two phases (the nematic and isotropic reality the determining structures in boundary layer

phase) are present in tire cell. Convection in the flows and whether simple models can be

presence of a first-order phase change is relevant constructed on their basis. To support these

to convection in the earth's mantle; ours are the efforts, three-dimensional velocity fluctuations are

first quantitative experiments relevant to this being measured in conjunction with visualization of

important problem. small oxygen microbubble tracers.

Engineering Research 9 1993

€^
So far as the effect of interfacial waves is although the relationship between PLS and other

concerned, a new wavemaker has been established regression methods has been

constructed and is in the process of being incomplete. A firm mathematical link has been

commissioned. The wavemaker is placed in the developed between PLS and statistical

tank from which the fluid enters the test section, significance testing. Based on these new results,

and care is being taken to suppress vortex PLS has been extended to deal with outliers

shedding which may give rise to nontypical and (robust estimation) and more general statistical

persistent flow structures. models, e.g. the measurement error model.

The thrust of the work has now turned to the effect

of interfacial waves on the streamwise funnel- Carnegie Mellon University

shaped structures described in the previous Chemical Eng Dept & Graduate $0

paragraphs. Direct numerical simulation in support School of Indus Admin 03-A

of these experiments has continued. It has been ittsbur PA 15213 894

found that if fluid tracer particles are injected into

numerical simulations, then they do trace a path Integration of Redesign Methodologies for

similar to the streamwise funnel-shaped vortices Chemical Processes

seen in the experiments. L. Biegler, I. Grossmann, G. Thompson, A.

Westerberg Direct simulation of the effect of interfacial waves

will be initiated, again, when the wall region Process redesign, commonly known as retrofit, is

structures have been better identified in order to a major task in the chemical industries. However,

understand the interactions between waves and most systematic design strategies have been

such structures. developed for new process and often do not apply.

This project addresses the development of

systematic design methodologies for the redesign

California Institute Of of chemical processes. This integrated approach

Technology deals with a broad range of problems in process

Chemical Engineering 210-41 $125,728 redesign. Here we discuss progress in the

Pasadena, CA 91125 03-A following areas:

91-3

Modeling for Process Control 1) Development of Efficient Optimization

M. Morari Algorithms for Discrete and Continuous Variables.

Efficient decomposition strategies for nonlinear

One key difficulty which stands in the way of programming have been developed for large-scale

application of many advanced control techniques process optimization. These are currently being

in the chemical process industries is the need for tailored to various problem types including

a model to describe the dynamic behavior of the optimization problems in flowsheet optimization,

process to be controlled. The objective of this parameter estimation and data reconciliation. The

research program is the development of a range of work also includes the solution of several large

new modeling techniques, in particular: scale combinatorial optimization problems that

development of techniques for building physics- frequently occur in chemical engineering

based, low order, nonlinear models with physically applications, namely, traveling salesman, and set

meaningful parameters, specificallyforthe purpose covering set packing, and set partitioning

of (robust) linear and nonlinear controller design; problems. These algorithms have also been

and development of methods for the identification developed on various sequential and parallel

of linear black box models and the associated computers such as the CRAY YMP, the Alliant

uncertainty description suitable for robust control FX/8 and the CMU Nectar network.

system design. 2) Redesign of multicomponent separation

This research program emphasizes methods that sequences. Our goal is an approach to redesign

are both mathematically lucid and industrially separation processes where the species display

effective. For example Partial Least Squares azeotropic behavior. These processes are

(PLS) has been highly regarded by practitioners complex, requiring recycles in principle. Mixing

Engineering Research 10 1993
can often be used to improve separation. For Benders decomposition method. The application

homogeneous azeotropic ternary mixtures, we of this method has been illustrated in bi-criterion

have two analysis results: (1) a technique to optimization problems for maximizing flexibility and

determine all possible products which can be minimizing investment cost. Also, an interesting

obtained in a single feed, two product. distillation relationship of our metric with Taguchi's quadratic

columns whether at total or finite reflux and (2) an loss function has been established.

approach to determine if an extractive agent will

allow separation of a binary mixture into desired (5) Optimization-based Methods for Process

products. Identification and Control. Optimization-based

algorithms are being developed for the control of

We are testing a new method to compute constrained, nonlinear processes; these are also

minimum flows in any column. We have a being used to control open loop unstable

methodology to produce automatically alternative processes. An extended stability theory has been

process configurations for such processes and developed and demonstrated, both for

have tested it on many examples, including a constrained and unconstrained systems. In

mixture of methanol, water, n-pentane and addition, both exterior and exact penalty function

acetone. We are also studying retrofit design for strategies have been developed and analyzed for

such processes involving trace species - i.e., for constrained model-predictive control algorithms.

waste recovery systems. Finally, tailored nonlinear and quadratic

programming algorithms are being developed for

(3) Redesign of energy management systems. more efficient solution of these problems. These

Mixed-integer nonlinear programming (MINLP) have been illustrated on a number of process

models have been developed for grassroots and examples.

the redesign problems. The unique feature of

these models is the fact that the level of energy

recovery and selection of matches is optimized Carnegie Mellon University

simultaneously without fixing temperature Dept of Elec & Comp Eng $100,860

approaches. We have recently developed a new Pittsburgh, PA 15213 03-C

global optimization algorithm for networks with 92-3

fixed topology. The basic idea relies on a rigorous Research on a Reconfigurable and Reliable

nonlinear convex NLP underestimator that Manipulators

provides tight lower bounds, and that is coupled p. Khosla, T. Kanade

with a spatial branch and bound method. Typically

not more than five NLP optimizations are required The goal of our research is to develop basic

to find the global optimum. Work is under way to design theory and methodology that will allow one

extend this method for the optimization of to determine both the kinematic and dynamic

topologies in which we intend to use as a basis a configuration of a manipulator capable of

recent LP/NLP based branch and bound method performing a given task. The motivation for this

for MINLP optimization. Finally, the interactive arises from the concept of a modular manipulator

program SYNHEAT is under development for the system comprising of a set of link and joint

implementation of these models. modules of various sizes which may be assembled

together in a desired kinematic configuration to

(4) Redesign for flexibility and reliability. The achieve a specific task. The joint and link

expected stochastic flexibility, a new measure that modules have consistent mechanical and electrical

integrates the two operability characteristics, has interfaces which will allow either semi-skilled field

been developed. The proposed measure can be personnel or another manipulator to rapidly

used to evaluate the probability of feasible configure a manipulator to meet specific task

operation, given uncertainties in process requirements. Since current manipulator systems

parameters and operational states. We have are fixed configuration, they lack the ability to

recently developed an NLP optimization model for perform widely varying tasks. Further, these

optimizating the stochastic flexibility in nonlinear manipulators are not fault tolerant - a loss of a

process models. This formulation, which embeds degree-of-freedom will result in a significantly the integration of multiple integrals using Gaussian reduced capability to perform the task it was

quadrature, is solved with the Generalized deployed for. In pursuing research on a

Engineering Research 11 1993
reconfigurable modular manipulator system, our The other line is also represented by two recent

goal is to not only create the technology but to publications45 : the first overcomes the traditional

push basic research for design of non redundant, limitation of neglect of the finite heat propagation

redundant, and fault tolerant manipulators. rate and develops a finite-time formalism based on

hyperbolic differential equations. The, second

This basic research effort will address the problem develops a Lagrangian treatment in which

of mapping tasks into a manipulator configuration, canonical variables are introduced for

formulation of control algorithms for the mapped nonequilibrium thermodynamics.

configuration, and experimental verification of the

developed ideas. Though it is not the primary

objective, we believe that building prototype 1. V. N. Orlov and R. S. Berry, "Analytical and

experimental modules for demonstrating our ideas numerical estimates of efficiency for an irreversible

will also contribute to the technology of modular heat engine with distributed working fluid," Phys.

manipulators. For configuring a manipulator from Rev. A 45, 7202 (1992).

task requirements, we have developed

methodologies that map the task requirements into 2. V. N. Orlov and R. S. Berry, "Power and

a specific non-redundant manipulator. The efficiency limits for internal combustion engines via

kinematic task requirements are used to determine methods of finite-time thermodynamics," J. Appl.

the link lengths and the orientation of the modules. Physics (in press, 1993).

And the dynamic task requirements are translated

to obtain the sizes and rating of the actuators or 3. V. N. Orlov and R. S. Berry, "Power output from

joints. an irreversible heat engine with a nonuniform

working fluid," Phys. Rev. A 45, 7230 (1990).

University Of Chicago 4. S. Sieniutycz and R. S. Berry, "Least-entropy

Dept of Chemistry $ 0 generation: Variational principle of Onsager's type

Chicago, IL 60637 06-C for transient hyperbolic heat and mass transfer,"

92-1 Phys. Rev. A 46, 6359 (1992).

Finite-Time Thermodynamics and Effective

Energy Use 5. S. Sieniutycz and R. S. Berry, "Canonical

S. Berry formalism, fundamental equation and generalized thermomechanics for irreversible fluids with heat

The period 1992-93 was fruitful. The work transfer," Phys. Rev. E 47, 1765 (1993).

followed two lines, the principal objectives of the

current work. One is the development of methods

of optimizing engines and processes by optimal University Of Chicago

control methods for distributed systems and The Enrico Fermi Institute $324,000

averaged systems. The other is the development Chicago, IL 60637 06-C

of a self -consistent thermo-hydro-mechanics for 93-3

nonequilibrium systems. The two publications Fundamentals and Techniques of

from the former illustrate that approach1 2: the first Nonimaging Optics

continues our earlier work3 by applying constraints R. Winston

of finite-time operation and by developing a

computational algorithm for cases with no analytic Nonimaging optics departs from the methods of

solutions. The second analyzes the internal traditional optical design to develop instead

combustion engine and exposes ways to improve techniques for maximizing the collecting power of

its efficiency or power delivery, in some cases by concentrating elements and systems. Designs

heating the system rather than cooling it, for part which exceed the concentration attainable with

of the cycle. This work is being continued with a focusing techniques by factors of four or more and

postdoctoral, Vladimir Kazakov, and Professor approach the theoretical limit are possible. This is

Anatoly M. Tsirlin, visiting in Fall, 1993. Both are accomplished by applying the concepts of

from the Institute for Optimization and Control Hamiltonian optics, phase space conservation,

Theory, Pereslavl-Zalessky, Russia. thermodynamic arguments, and radiative transfer

Engineering Research 12 1993
methods. In the early nonimaging designs the apparatus. The results provide checks of the

mighty edifice of aberration theory was dismantled numerical and theoretical work.

and replaced by a single key idea. According to

this, maximum concentration is achieved by The asymptotic and experimental portions of the

ensuring that rays collected at the extreme angle project are done. The numerical study is still under

for which the concentrator is designed are way. The numerical results to date are in good

redirected, after at most one reflection, to form a agreement with the asymptotic and experimental

caustic on the absorber. This principle proved findings when the particle Reynolds numbers are

sufficiently elastic to accommodate most boundary smaller than unity.

conditions in two dimensions (i.e., linear

geometry). Ideal solutions in three dimensions

have also been formulated. Our work on vector University Of Connecticut

flux has led to a reexamination of the foundations Dept of Mechanical Engineering $50,000

of radiometry with emphasis on observable effects. Storrs CT 06268 01-A

Our theoretical work on nonimaging designs has 92-3

led to demonstration of ultra-high flux from sunlight

which exceeds previous results by substantial Engineering Science Software

factors. Design algorithms have been developed

for reflectors that are functionals of the desired Smithfield, R 02917 $48,000

irradiance. This permits new solutions which solve 01-A

classical problems in illumination from extended 92-3

sources. A Micromechanical Viscoplastic Stress-Strain

Model with Grain Boundary Sliding

E. Jordan, K. Walker

Clarkson University In the first part of the program a model that

Dept of Chemical Engineering $62,000 allowed polycrystalline elastic and viscoplastic Potsdam, NY 13676 01-C constitutive behavior to be predicted from

91-3 crystallographic slip in single crystals was

Lift and Drag Force on on Droplets o s and developed and verified in high temperature biaxial

Particles in Wall-Bounded Flowspolycrystal experiments. polycrystal J. McLaughlin

In the ongoing research the goal is to predict the The goal of this research is to obtain quantitative degree of heterogeneity of deformation and verify information about the lift and drag forces that act hese predictions experimentally. Two types of

on small droplets or particles that translate through theoretical models have been used to predict theoretical models have been used to predict shear flows. Such forces affect the motion of heterogeneity. The first model involves averaging droplets or particles near a rigid wall. Thus, a the effect of neighboring grains while the second

knowledge of the forces is needed to describe model using a unique Green's function method,

processes such as the deposition of aerosols on allows arrays of grains to be modeled explicitly.

solid surfaces. Calculations done to date show that the selfconsistent model significantly underestimates the The approach used in the research involves a heterogeneity compared to the more realistic

combination of analyttical, numerical, and explicit model. The most extreme heterogeneity laboratory work. Asymptotic expressions have found in studying 50,000 grains was not nearly as

been derived for the lift and drag forces in the great as in a pair of artificially constructed arrays regime of small Reynolds numbers. In most designed to produce extreme heterogeneity.

situations of practical importance, however, the

droplet or particle Reynolds numbers are not small The strain in individual grains was recorded in a

compared to unity. At finite Reynolds numbers, coarse grained sample using the Moire

direct numerical simulations of the three- interferometry apparatus at INEL. Reduction of

dimensional flow field around a sphere in a shear this raw data to strain fields is now ongoing.

flow have provided the forces. The experiments Preliminary results show that the inelastic

involve measurements of particle migration response is extremely heterogeneous. The

velocities in a vertical homogeneous shear flow modeling software is now being enhanced to

Engineering Research 13 1993
include constitutive model with an appropriate distribution function which is described by a set of

abrupt yield behavior to see if the observed points with a continuous set of fractal dimensions.

extreme heterogeneity can be modeled. Neutron Our observations of multifractals behavior were,

diffraction experiments are to commence on we believe, the first to be observed in fluidJuly 22, 1993 at Argonne National Labs. In these structure vibrations.

experiments elastic strains will be measured for

both surface and interior grains. Thus data will In January 1992, Mr. George Muntean visited

nicely complement the Moire' data which reveals Argonne National Laboratory and reported to Dr.

the total strain of surface grains only. Developing S.S. Chen our findings on muiltifractal

models to predict grain to grain heterogeneity and measurements. He subsequently presented a

verifying these models is a basic element in paper at the DOE Grantees meeting later this past

modeling mechanical behavior. Such heterogene- spring. A revised paper has been submitted to the

ity is important in fatigue which starts in the most Journal of Fluids and Structures, and is currently

unfavorably oriented grain, in modeling stress under review.

induced phase transformation and in grinding

where heterogeneity may influence surface finish. ii) The design of the cross-flow, tube row

experiment began last summer and was

completed this fall. These experiments parallel the

Cornell University work of Cai and Chen (1992). In the Cornell

Mechanical & Aerospace Engineering $62,988 experiments the center tube of a five-tube set

Ithaca, NY 14853 01-A suspended on a flexible rod. The tube motion is

91-3 limited by motions stops, thus introducing a strong

Chaos in Fluid-Structure Systems nonlinearity in the tube stiffness. Preliminary

F. Moon experiments were carried out in water. The

vibration amplitude versus flow velocity shows the

Two principal experiments were carried out under instability onset (Hopf bifurcation) and the vibration

this grant during the second year of this project: saturation when the impact constraints limit the

chaotic motion. This response was found to

i) Forced vibration of a single flexible tube with depend on whether the flow velocity was

internal flow, ii) Cross flow measurements of increasing or decreasing.

chaotic vibrations of a flexible tube in a five tube

row. The vibration frequency was found to depend on

the flow velocity. There is some evidence that the

i) In the first set of experiments, begun in the first periodic motion at the onset of flutter to chaotic

year, we explored multifractal phenomena, which motion transition occurs through quasiperodic

describe the transition from quasiperiodic to vibration.

chaotic vibrations. Quasiperiodic vibrations were

observed in earlier experiments by Dr. G. Scott At the present time we are carrying out the

Copeland in flow through a long tube with an end calculations of the fractal nature of the Chaotic

mass. These results were reported an a Ph.D. motion with the goal of establishing the low

dissertation in Summer 1990. By introducing a dimensional nature of the dynamics. At the same

periodic-forcing of the tube in an adaptation of this time we will correlate our findings with a similar

experiment, we were able to more easily study experiment at Argonne National Laboratory to

this transition from quasiperiodic to chaotic establish the validity of the fractal dimension

vibration. This study was motivated by work in the technique in determining chaos in such flows. The

mid 1980's on forced Rayleigh-Bemard flow which next stage of this work walk involve experiments in

showed a linkage between quasiperiodic motion cross flow of air past a row of tubes as described

and the circle map. in the next section on our proposed research for

the third year of this project.

In the forced tube experiment we were able to

show a similar connection to the circle map, and in In 1993 a new wind tunnel facility has been

particular, the multifractal nature of the breakup of constructed and we are investigating nonlinear

the torus in c phase space. A multifractal is a dynamics of a tube row in cross flow.

Engineering Research 14 1993
Cornell University Dartmouth College

Sibley School of Mech & Aero Eng $105,818 Thayer School of Engineering $ 0

Ithaca, NY 14853 01-C Hanover, NH 03755 06-C

91-3 91-2

Experiments in Turbulent Mixing Mixing and Settling in Continuous Metal

Z. Warhaft Production

H. Richter

Our experimental studies of passive scalar mixing

and transport in turbulent flows are motivated by a In modem metallurgical processes metal is

desire to understand better the fluid mechanics of produced continuously and directly from ore in

chemical reactions, combustion and environmental

pollution, all of which occur in turbulent single converters operated in horizontal mode

background flows. Towards this end we are using submerged gas injection into the liquid

studying passive thermal dispersion in a jet, and metal-slag bath. These reactors promise

mixing of temperature fluctuations in substantial fuel savings and much better control of

homogeneous grid generated turbulence. pollutants than common practice. The injected

gas must create sufficient turbulence to provide

The jet experiment, in which a fine circular heated excellent gas-liquid contact in order to maximize

wire is placed close to the jet exit and concentric heat and mass transfer in the bath, but this

with it, is an analogue of a heated line source in turbulence must be selectively localized to provide

grid turbulence, a much studied subject. The adequate phase separation zones of metal and

motivation in both cases is to determine the rate at slag between active turbulent zones.

which a scalar contaminant mixes disperses when

it is introduced at a scale much smaller than that Knowledge of liquid entrainment into the bubble

of the velocity field. Our results show that in the plume created by submerged gas injection, and of

jet, mixing is faster due to the shear and that by liquids separation are of fundamental value in

about 20 jet diameters downstream complete designing reactors, howeverthese phenomena are

mixing has occurred. Examination of various also of generic interest to other processes, such

quantities such as the probability density function as the current major DOE-AISI direct steelmaking

(pdf) and conditional statistics provides insight into process or severe accident analysis of nuclear

the dynamical details of the mixing process. reactors.

Our work on grid turbulence has concentrated on In this work mixing caused by submerged gas

the behavior of temperature spectra and the scalar injection into a bath and subsequent phase

pdf. We have shown that the pdf, under certain separation of two immiscible liquids representing

circumstances, has tails much broader than would slag and metal are being studied experimentally

be expected from a Gaussian distribution and that and analytically. Novel instrumentation for local

the temperature spectra obey Obukhov-Corrsin- measurement of volume fractions of gas and

Kolmogorov scaling even at very low Peclet liquids has been developed. First experimental

numbers and without local isotropy in the scalar results of liquid flow velocities induced by gas

field. injection and volume fractions of gases and liquids

in and around the gas plume as well as

complementing numerical results are available.

Engineering Research 15 1993
Dartmouth College Duke University

Thayer School of Engineering $120,600 Department of Physics $60,000

Hanover, NH 03755 01-C Durham, NC 27706 01-C

92-3 93-3

Two-Phase Potential Flow Experimental and Analytical Investigations

G. Wallis of Flows in Porous Media

R. Behringer

The objective is to develop theorems for twophase potential flow analogous to those existing Research objectives for this project include the

for single phase flow. development and application of two novel

techniques for studying flow in porous media.

Using one function, the "exertia," which describes These techniques are: 1) magnetic Resonance

the external fluid inertia due to relative motion of Imaging (MRI), and 2) a novel shadowgraph

suspended particles, it has been possible to derive technique, to be referred to as MST (Modified

the average stress tensor, kinetic energy, overall Shadowgraph Technique). The primary goals are

momentum flux tensor and equations of motion for

uniform systems of particles and the effective to use these techniques to characterize and

Bernoulli equation for the fluid flowing through a understand convective flows in porous media,

stationary array of particles. including pattern selection, secondary instabilities,

and time dependence. MRI provides both local

Recent developments include more general des- velocity and local fluid density information. MST

criptions of the mean particle stresses and the provides pattern information easily and efficiently.

averaged Bernoulli equation for the fluid when Both techniques are fully operational. An

both phases have a general motion. Links have important finding is that the geometric structure of

also been established between this approach and the medium plays a fundamental role in pattern

Guerst's variational methods including the deriva- selection. Media constructed from periodic arrays

tion of equations of motion for each phase it being of bars show a well defined transition to

possible for the dispersed phase to be convection and sharply defined parallel convection

compressible. The equations of motion for each rolls with orientation determined by the symmetry

phase have also been expressed in terms of a of the array. Media consisting of a random array

mutual "interfacial pressure tensor" that is related of holes show disordered patterns and an

to both the average stress in the dispersed phase imperfect bifurcation to convection. Numerical

and the net force on the continuous phase. This studies are underway to probe the role of media

interfacial pressure tensor is also closely coupled structure on the pattern. Studies where the

to the Reynolds stresses in the continuous phase. median is constructed from semi-ordered and well

ordered arrays of spheres show patterns near

The exertia and added-mass coefficients have onset with more symmetry than the random-hole

been computed for various geometrical media but less symmetry than the periodic bar

arrangements of spheres, both in an infinite array media.

and in tubes. Comparable measurements were

made by measuring the natural frequency of

oscillation of such arrays in water. Future Idaho National Engineering Lab

experiments are planned in which more properties, Bioprocess & Environ Assessment $109,000

such as pressure fluctuations, are measured. Idaho Falls, ID 83415 06-A

89-3

Theoretical and experimental efforts are underway Three Phase System Modelling

to obtain realistic interphase forces including the G. Andrews

effects of viscosity and drag. Computations show

that the effects of pressure gradient, added mass, The behavior of bubbles of gas in liquids

phase change and drag do not add linearly except containing surface-active solutes is critical to the

at low Reynolds numbers. This has implications for performance of processes like floatation,

the transient response and stability of fluidized fermentation, and gas/liquid reaction. These

beds.

Engineering Research 16 1993
bubbles are usually in the millimeter size range, Based on the development of a fundamental

ellipsoidal or cap-shaped rather than spherical and understanding of the fluid mechanics and

rise with a Reynolds number, Re, of several thermodynamics of high temperature,

hundred. This project is developing a theoretical nonequilibrium, flowing systems, process

model for such bubbles. It includes mass transfer improvements are sought. These improvements

of surfactants between the liquid and the bubble are: controlled/minimized entrainment of external

interface, the effect of the absorbed surfactant on atmospheres, increased velocities, increased

the interface force balance and thus on the plasma volume, and minimized jet fluctuations.

mobility of the interface and the hydrodynamics in The desired result is to deliver to the substrate a

the boundary layer around the bubble. The particle ensemble at higher velocities with less

objective is to predict gas/liquid mass transfer variance in temperature, velocity, molten fraction,

rates, particle capture rates by the rising bubble and chemical composition. Ultimately, a better

and ultimately bubble shape as a function of understood process will allow improvements in

surfactant concentration. New forms of integral coating adhesion and strength while other

boundary layer theory have been developed to characteristics, such as porosity, can be specified

predict the behavior of boundary layers on a and controlled. This ability leads to the possibility

moving spherical interface at Re of a few hundred. of engineering unique new coatings with graded

composition, porosity, etc. and enhanced

Results are significantly different from previous properties for advanced applications.

theories based on creeping flow (Re<1)

hydrodynamics. Experiments on the capture of

latex particles are being conducted for comparison Idaho National Engineering Lab

with the theory. Materials Science Division $250,000

Idaho Falls, ID 83415 03-A

93-3

Idaho National Engineering Lab Application of Intelligent Control Systems

Applied Physics & Optics $493,000 to Mixed-Culture Bioprocesses

Idaho Falls, ID 83415 06-A J. Johnson, D. Stoner, G. Andrews

90-3

In-Flight Measurement of the Temperature of The aim of this project is to show that the

Small, High Velocity Particles productivity of mixed-culture bioprocesses can be

J. Fincke greatly increased by applying intelligent systems to

the process control problem. Controllers will be

The objective is to fundamentally improve the developed by combining the tools of intelligent

thermal plasma spray process. Modifications to control including fuzzy logic, expert systems, and

conventional torches are being examined along neural networks. The ability of a mixed microbial

with a new generation of high-velocity, high-power culture to adapt to changing conditions will be

(HVHP) plasma torches. These devices offer matched by the ability of the control system to

larger plasma volumes at higher velocities while learn about process performance continuously.

minimizing power fluctuations due to anode spot Sensors will be developed to inform the control

movement. Higher particle velocities decrease system about the activity of the dominant strains of

residence time, an important factor in minimizing microorganisms in the mixed culture. This will be

oxidation reactions, and generally produce a combined with expert knowledge on the

higher density and more consistent coating. The metabolism and biochemistry of these strains

chemical dynamics of high velocity flow fields is incorporated as fuzzy logic rules in the controller.

also expected to lead to large departures from

equilibrium, significantly increasing ion and These control concepts will be demonstrated in the

dissociated species populations. Since surface laboratory using the oxidation of ferrous iron by

recombination increases plasma/particle heat Leptospirillum ferrooxidans as a model system. A

transfer rates, this can be a significant advantage, controller will be developed first for a pure culture

yielding fully molten particles with less residence of this organism in a chemostat, the control

time. objective being to maximize the oxidation rate

Engineering Research 17 1993
without the appearance of ferric iron precipitates. Idaho National Engineering Lab

The culture complexity will then be progressively Materials Technology Group $430,000

increased by adding an acidophilic heterotrophic Idaho Falls ID 83415-2218 01-A

bacterium that consumes organic matter known to 90-3

inhibit Leptospirillum, and a protozoa that feeds on Elastic-Plastic Fracture Analysis Emphasis the bacteria. Appropriate control rules will be on Surface Flaws

developed and implemented at each step. W. Reuter

The objective is to improve design and analytical Idaho National Engineering Lab techniques for predicting the integrity of flawed

Energy Res & Applications Dept $232,000 structural components. The research is primarily

Idaho Falls, ID 83415 06-A experimental, with analytical evaluations guiding

90-3 the direction of experimental testing. Tests are

Modeling of Thermal Plasma Processes being conducted on materials ranging from linear

J. Ramshaw, C. Chang elastic to fully plastic. The latter extends beyond

the range of a J-controlled field. Presently,

Optimization of thermal plasma processing compact tension and bend specimens are being

techniques requires a better understanding of the used to develop state-of-the-art fracture toughness

space- and time-resolved flow and temperature results. Specimens containing surface cracks are

distributions in the plasma plume and of the used to simulate the fracture process (crack

interactions between the plasma and injected growth initiation, subcritical crack growth, and

particles. The present research is directed toward catastrophic failure) that may occur in a structural

the development of a comprehensive component. computational model capable of providing such

information. The model is embodied in the LAVA Metallography and microtopography techniques

computer code for two- or three-dimensional have been developed to measure crack tip

transient or steady state thermal plasma opening displacement and crack tip opening angle

simulations. The plasma is represented as a for comparison with analytical models. Moire

multicomponent ideal gas governed by the interferometry techniques are used to evaluate and

compressible Navier-Stokes equations. quantify the deformation in the crack region. These

Multicomponent diffusion is calculated by a studies have resulted in the ability to predict crack

self-consistent effective binary diffusion growth initiation of a structure using constraint and

approximation, including a new formulation for fracture toughness data obtained from standard

ambipolar diffusion of charged species. fracture toughness specimens. Future research will

Subgrid-scale and k-epsilon turbulence models are focus on predicting the stable crack growth

included. Dissociation, ionization, and plasma process in base metal and the fracture process in

chemistry are treated by means of general explicit weldments.

and implicit chemistry routines for treating slow,

fast, and equilibrium chemical reactions. Discrete Diffusion bonded specimens are being used to

particles interacting with the plasma are simulate weldments. These specimens are used to

represented by a stochastic particle model which study the ability of existing models to predict the

allows for distributions in particle sizes, shapes, fracture process for weldments.

temperatures, etc. Departures from local

thermodynamic equilibrium are accounted for by a This project is a collaborative program with the

two-temperature model which permits the electon Massachusetts Institute of Technology.

and heavy-particle temperatures to differ.

Nonequilibrium populations of excited levels are

treated as separate chemical species, with

collisional and radiative transitions between levels

modeled as kinetic chemical rate processes.

Applications of the model to date include realistic

simulations of plasma jets and plasma spraying,

and detailed studies of excitation nonequilibrium in

plasma jets.

Engineering Research 18 1993
Idaho National Engineering Lab particularly, superconducting properties, need to

Materials Technology Group $530000 be measured non-invasively and spatially in order

Idaho Falls, ID 83415 03-A to aid the fabrication process.

90-3

Intelligent Control of Thermal Processes Past work has concentrated on developing a

H. Smartt, J. Johnson noncontacting AC induced current measurement

technique that can determine critical currents on a

This project addresses intelligent control of thermal local scale with high resolution. This technique

processes as applied to materials processing. can be used in conjunction with external applied

Intelligent control is defined as the combined fields and DC transport currents to determine

application of process modeling, sensing, artificial spatial variations in critical current dissipation. Its

intelligence, and control theory to process control. operation is based on inducing the critical state

The intent of intelligent control is to produce a and full field penetration into the sample directly

good product without relying on post-process under the probe. With the aid of the "critical state"

inspection and statistical quality control model for flux pinning, local critical current values

procedures. The gas metal arc welding process is have been determined empirically without any

used as a model system; considerable connections to the sample.

fundamental information on the process has been

developed at INEL and MIT during the past eight Current research is concentrated on silver

years. Research is being conducted on an sheathed tape geometries and the development of

extension of the fundamental process physics, an analytic approach to predicting the critical state

application of knowledge-based dynamic in geometries utilizing non-uniform applied fields,

controllers and signal/image processors, and as are found in most NDE applications. An

development of noncontact sensing techniques. integral equation has been found that can be

Tasks include analytical modeling of nonlinear solved iteratively to determine the flux front profile

aspects of molten metal droplet formation and in the tape geometry. This approach shows

transfer; developing fundamental ties between promise for application to other geometries

knowledge-based controllers (including artificial involving the critical state with demagnetization

neural networks and fuzzy logic based effects.

connectionist systems) and classical and

advanced control methods; and advanced optical

and ultrasonic sensing, including the propagation University Of Illinois

and interaction of ultrasound in metallic solid and Coordinated Science Laboratory $127,000

liquid media. Urbana, IL 61801 03-A

91-3

This project is part of a collaborative research Model Building, Control and Optimization of

program with the Massachusetts Institute of Large Scale Systems

Technology. T. Basar, P. Kokotovic

This program involves fundamental research on

Idaho National Engineering Lab the modeling, control, and optimization of large

Nondestructive Mat'ls Charac Grp $200,000 scale systems. The main theme is model

Idaho Falls, ID 83415-2209 03-B simplification for control and decision making. It

90-3 encompasses both linear and nonlinear models,

Nondestructive Evaluation of and deterministic and stochastic systems with

Superconductors regular and/or singular perturbations. Research

K. Telschow issues addressed are in modelling, optimization,

stabilization and coordination, as well as in the

This project is concerned with the development development of implementable control policies.

and application of new nondestructive evaluation Their common goal is to broaden the applicability

(NDE) techniques and devices for the of the concept of multimodeling as a systematic

characterization of high-temperature approach to model simplification through

superconducting materials. Microstructural and, decomposition/aggregation of linear and nonlinear

large scale systems.

Engineering Research 19 1993
One area of current research is the robustness of University Of Illinois

a controller, designed based on a nominal linear or Dept of Mechanical and $66,169

nonlinear system, to unmodeled fast dynamics and Industrial Engineering 01-A

external norm-bounded disturbances. The issue Urbana IL 61801 93-3

here is not only the robustness analysis of a given

controller, but also the design of optimally robust Stress Induced Phase Transformations

controllers that are least sensitive to such H. Sehitoglu

structural and external perturbations. Another

topic of study at the present is the relationship Understanding stress-induced phase

between deterministic and stochastic formulations transformations is of paramount importance in

for uncertain systems, from the point of view of modeling the behavior of engineering materials

model simplification, and robustness to unmodeled and components. From the material behavior

dynamics and nonlinear perturbations. standpoint, transformations generate internal

(micro) stresses which alter the constitutive

behavior, and from the component standpoint

University Of Illinois transformation strains may result in dimensional

Dept of Chemical Engineering $232,000 changes and alteration of macroscopic stress

Urbana, IL 61801 01-C fields. The transformation strains are strong

82-3 functions of the applied stress state since

Gas-Liquid Flow in Pipelines favorably oriented planes transform in the course

T. Hanratty of loading. Several unique experiments under

combined shear stress - hydrostatic pressure are

The long range goal of this research is to describe conducted on steels, containing retained austenite,

the macroscopic behavior of gas-liquid flow in order to measure and study anisotropic

systems by developing a phenomenological transformation strains. Test specimens are

understanding of small scale interphase subjected to externally applied pressures in excess

interactions. The simplified systems of fully of 700 MPa. The compressive hydrostatic

developed flow in vertical and horizontal pipes are stresses would increase the extrinsic ductility of

being used. Specific goals are (1) to obtain the material, and hence permit high magnitudes of

measurements of drop sizes in vertical annular the stress-induced and strain-induced

flow in order to provide an understanding of the transformations. Based on these experiments, the

rate processes that govern entrainment, (2) to work will set the background to evaluate the

study the role of gravity in causing an asymmetric theories proposed, and lay the foundation for new

distribution of the liquid and of the flow field in ones with particular emphasis on complex

horizontal annular flow, (3) to use new results on changes in transformation strains. The basic

the formation of slugs to develop an understanding information obtained from the work will generate

of the frequency of appearance of slugs in improved understanding of transformation under

horizontal slug flow, and (4) to study the role of contact loadings and transformation toughening

waves in enhancing transport in stratified gas- phenomenon in metallic and non-metallic

liquid flows. materials.

Studies of droplet deposition in vertical annular

flows have revealed the surprising result that

deposition rates are independent of droplet University Of Illinois At Chicago

concentration at large enough concentrations. Energy Resources Center $79,980

This is being interpreted with direct photographic Chicago, IL 60680 01-B

measurements. A mapping of the gas phase 93-1

velocity shows the existence of secondary flows Heat Transfer to Viscoelastic Fluids

both for horizontal stratified flow and for horizontal J. Hartnett

annular flow. Of particular interest is the discovery

that spatial variations of drop concentration can Numerical studies of the steady laminar flow heat

induce these flows. transfer behavior of non-Newtonian fluids through

rectangular ducts have been carried out. The

Engineering Research 20 1993
Reiner-Rivlin model which gives rise to secondary A study has also been carried out of the accuracy

flows in non-circular ducts is used to investigate of the singularity method for the direct numerical

the influence of elasticity on the flow. Finite simulation of the potential flow motion of many

difference methods are developed to obtain the particles in a liquid.

heat transfer results for the H2 thermal boundary

condition for difference combinations of heated Current efforts center on the simulation of

and adiabatic walls. suspensions of non-spherical particles in the

potential- and Stokes-flow limits.

The influence of the second normal stress

coefficient, the Reynolds number, the Peclet

Number, and the aspect ratio on the heat transfer Robert H. Kraichnan, Inc.

are considered. It is found that the secondary flow 303 Potrillo Drive $66,440

has a relatively weak influence on the pressure Los Alamos, NM 87544 01-C

drop but the effect on heat transfer is increased by 93-3

a factor of 2 to 3 as compared to the case of a Turbulence Theory

purely viscous fluid. The predicted behavior of the R. Kralchnan

Nusselt number for the Reiner-Rivlin fluid is found

to be in good agreement with experimental results. Turbulent fluid motion plays an essential role in

atmospheric and oceanic dynamics, in

aerodynamics, and in chemical and other industrial

Johns Hopkins University processes. Turbulence is so complicated in detail

Mechanical Engineering Dept $149,980 that apt statistical description is essential, and

Baltimore, MD 21218 01-C there is strong motivation for new theoretical

92-3 approaches that extract essentials of the dynamics

Numerical and Physical Modeling of Two- in a compact fashion. The present project is

Phase Flow Phenomena at Large Reynolds devoted to these objectives. One part of the work

Numbers has been collaboration in the design and

A. Prosperetti interpretation of unprecedented high-resolution

computer simulations of turbulence at Los Alamos

The ultimate purpose of this study is to develop National Laboratory. This has led to some

accurate averaged- equations models of disperse clarification of the strongly- intermittent

multi-phase flows of engineering significance. very-small-scale structure of turbulence; the data

Analytical means are used to derive the form of are consistent with some earlier theoretical

the equations and direct numerical simulations to predictions. Another accomplishment with the

effect their closure at finite volume fractions. simulation data has been verification of

fundamental similarity hypotheses made years ago

A new method of phase averaging has been by Kolmogorov and recently challenged. On the

developed and applied to rigid and compressible theoretical side, work has continued on methods of

spheres in potential flow and in Stokes flow. approximating turbulent flow-field statistics by

Analytical results have been obtained in the dilute simple nonlinear transformation, or mapping, of

limit and numerical ones for finite volume fractions. fields with known statistics ("mapping closure").

The method is quite flexible and general and has Progress has been made thereby in understanding

also been applied to the derivation of averaged some key probability distributions that have been

energy equations at small Peclet number and of measured in turbulence simulations and in the

the particle stress tensor in potential flow. laboratory. An additional project, involving both

computational and theoretical work, has been the

In separate study, the viscous flow around two study of Lagrangian turbulence statistics (statistics

slip-free spheres (a useful approximation for gas measured while moving the flow).

bubbles) has been studied computationally to

evaluate the methods currently used to model

viscous effects at large Reynolds numbers.

Engineering Research 21 1993
Lawrence Berkeley Laboratory Lovelace Medical Foundation

Accelerator & Fusion Res Div $132,000 Bioengineering Research $51,475

University of California 06-C Albuquerque, NM 87108 03-B

Berkeley, CA 94720 90-3 93-3

Two-Phase Flow Measurements by NMR

Studies in Nonlinear Dynamics E. Fukushima, S. Altobelli, A. Caprihan

A. Kaufman, R. Littlejohn

The objective of this grant is to apply NMR to

Our research concerns the development of study how mixtures of different phases flow. The

methods of modem nonlinear dynamics with concentration profile of one or both of the phases

applications to problems in physical and undergoing flow as well as velocity profile and

engineering sciences. We have been especially other more esoteric quantities such as acceleration

involved with Hamiltonian dynamical systems and and diffusion can be measured without interfering

the application of differential geometric and with the flow. The non-invasive measurement of

topological methods. A main area of application is such parameters is especially difficult for

wave systems, in which we have taken a broad, concentrated mixtures that are opaque to the

interdisciplinary perspective. Our interests have standard measurement medium such as light and

included the propagation, spectra, mode sound waves but NMR works very well provided

conversion, and tunnelling of waves. Major we examine proton containing liquids, e.g., water

divisions of the program are: (1) A study of the and oil, in nonmetallic containers.

properties of coupled wave systems, including

elastic"waves in solids, electromagnetic waves in Steady flows of concentrated suspensions in a

optical media or plasmas, nuclear wave functions circular pipe, first with a constant cross-section

and then with a step expansion and contraction,

in molecular physics, and many others; (2) The have now been studied. Because NMR imaging

development of a new method for decoupling is a fairly slow method, it is very important to

coupled wave systems, including systematic

adiabatic perturbation schemes for this purpose; extend the NMR method to faster flows. As a

(3) The development of asymptotic quantization point of reference, velocity images have been

methods for coupled wave systems, i.e., the made in tens of minutes whereas the achievement

determination of normal mode frequencies and of similar results in fractions of seconds will be a

eigenfunctions; (4) Investigation of differential specific objective for the next few years.

geometric and topological concepts such as

Berry's phase, gauge structures, and topological

singularities (such as monopole strings) which University Of Maryland

generically occur in coupled wave systems; (5) A Dept of Mechanical Engineering $70,896

systematic study of mode conversion (otherwise College Park, MD 20742 01-D

called Landau-Zener transitions), in which we 93-3

apply bifurcation and catastrophe theory to Characterization of Metal Cutting Dynamics

categorize the basic types of mode conversion B. Berer, . Minis

which can occur; (6) Investigations into coherence

and radiometry in optics; (7) The development of The dynamics of metal cutting significantly affects

theories of mode conversion applicable when the quality of machined parts and the productivity

nonlinear effects are important; and (8) A study of of the machining operation. Cutting instabilities

the non-Abelian gauge fields which occur in the for large material removal rates result in

separation of rotational and internal coordinates in substantial annual losses of productivity, energy

the n-body problem (with applications to celestial and material. The goal of this research project is

mechanics, satellite control, and atomic, molecular, to contribute towards efficient machine tools that

and nuclear physics). require minimum human intervention. This will be

accomplished through the intelligent control of the

cutting process.

Engineering Research 22 1993
The first objective of this study is the verification of The main research objectives of the ongoing

the following three conclusions reached by the Pi's research can be briefly summarized as follows:

from the analysis of experimental measurements further development of scalar and vector Preisach

of tool work piece relative acceleration: i) The type models of hysteresis (superposition models,

/dimensions of attractors associated with noisy two-input models for magnetostrictive and

turning data can be successfully estiriated with piezoelectric hysteresis and their tensor

existing algorithms; ii) Pre- and mild chatter are extensions, feedback Preisach-type models),

characterized by attractors of low dimension; iii) development of Preisach-type models for viscosity

Qualitative properties of the dimension function (aftereffect), application of Preisach-type models to

discriminate between steady and pre-chatter the description of superconducting hysteresis and

cases. evaluation of hysteretic losses in hard

superconductors, software implementation of the

The second objective is the determination of the Preisach hysteresis models, extensive

applicability of other measures of attractor experimental testing and verification of hysteresis

structure, and asymptotic behavior to the analysis models, investigation of penetration of

of cutting data. electromagnetic fields into nonlinear hysteretic

media. It is hoped that, as a result of this

The third objective is the use of dimension, research, the Preisach-type models of hysteresis

Lyapunov exponents and other measures of will emerge as a useful and indispensable tool in

dynamic behavior in characterizing pre-chatter engineering research and design problems.

states thus providing a rule base for controlling the

cutting process.

University Of Maryland Based Based on on the the patterns patterns of of change change of of the the University Electrical Engineering Of Maryland Department $83,537 fundamental descriptors of dynamical behavior, a Baltimore MD 21228 03-B

rule base will be developed to be used for chatter 92-3

avoidance. The rule base will be integrated into a Pulse Propagation in Inhomogeneous

system to control speed and feedrate in response Optical Waveguides

to changes in the dynamic measures that signify C. Menyuk

the imminence of chatter.

We are presently working on three separate Currently computer programs for the computation rojects. First, we are studying randomly varying

of the dimension function, D(y), Lyapunov birefringence in optical fibers and its impact on

exponents, noise reduction, singular spectrum, both soliton and NRX communication systems. To

noise floor, and attractor construction with singular do that, we are carrying out Monte Carlo

vectors have been implemented. A machine tool simulations of large numbers of fibers. We have

has been instrumented and verification testing is already demonstrated that optimal results are

under way. obtained for both types of communication system

if one operates with the smallest possible amount

of randomly varying birefringence and if the scale

University Of Maryland length for the birefringence fluctuations are on the

Dept of Electrical Engineering $86,033 same scale as the beat length. Second, we are

College Park, MD 20742 06-C studying passively modelocked fiber laser systems

92-3 such as the figure-8 laser. These lasers are of

Mathematical Models of Hysteresis potential importance as sources in future, very

. Mayergoyz high bit rate communication and switching

systems. Our approach, which is based on using

This research is concerned with the development computers to carry out a stability analysis of the

of mathematical models of hysteresis. These laser's operation, is new in this field. Previous

models are phenomenological in nature and, for studies relied on either complete, ab initio

this reason, they can be applied to the description simulations or on purely analytical theories. Our

of hysteresis regardless of its physical origin. approach allows us to accurately explore large

Engineering Research 23 1993
regions of parameter space and optimize the gears are carefully monitored. Preliminary

laser's operating conditions. Third, we are simulation results indicate that driveline flexibility

studying solid state devices. In the last year, we does have significant effects on the system

have been exploring the advantages of using stability. Backlash can be out of control, if the

Richardson extrapolation to stabilize several well- controller is not properly designed.

known schemes, and we have found that it is very

beneficial. In the future, we intend to apply this

approach to the study of quasi-phase-matched University Of Maryland

second harmonic generation which is of Dept of Mechanical Engineering $132,000 importance in obtaining sources which can write College Park, MD 20742 01-C

higher capacity compact disks. 91-3

Lagrangian Analysis of Contaminant

Dispersal in Bounded Turbulent Shear Flows University Of Maryland J. Wallace, P. Bernard, J. Balint

Dept of Mechanical Engineering $75,000

& Systems Research Inst 03-C The objective of this project is to study the

College Park, MD 20742 92-3 physical processes associated with turbulent

scalar transport in shear flows with a view towards

The Mechanics of Redundantly Driven developing novel techniques for predicting

Robotic Systems contaminant dispersal in the environment. A

L. Tsai closely coordinated experimental and theoretical -

research program is followed combining wind

Gear backlash introduces rattling and position tunnel experiments using hot- and cold-wire

uncertainty in robotic systems. To overcome probes, smoke visualizations arid image these difficulties, an innovative concept utilizing processing, with numerical simulations.

redundant drives to ensure positive coupling of Temperature and concentration contours of point

gear meshes has been conceived. The objective and line source diffusion in the boundary layer

of this research is to gain further understanding of obtained from visualization data and from a

the mechanics associated with such manipulating numerical simulation of channel flow are being

systems. Such systems can also be found in compared in order to verify the accuracy of the

tendon-driven manipulators, wherein the redundant two techniques. A Lagrangian decomposition of

drives are used to maintain positive tension in the scalar transport correlation into fundamental

tendons. physical processes is being carried out using

ensembles of particle paths computed in the

Force transmission characteristics associated with simulation of turbulent channel flow. This provides

n-DOF manipulators controlled by n+l actuators insight into the physical mechanisms underlying

has been investigated. It is shown that actuator transport and how they may be modeled.

torques required to act against externally applied

forces are functions of the structure matrix, its null Images from the boundary layer flow visualization,

vector, and the Jacobian matrix. Design equations at Re-1070, of the line source of smoke have been

for synthesizing a manipulator to possess isotropic digitized and analyzed. It has been determined

transmission characteristics have been derived. that there is a strong correlation between the

The theory will be extended to n-DOF momentum and mass fluxes and the vortical

manipulators controlled by more than n+l structures of the boundary layer wall region. In

actuators. addition, temperature measurements have been

carried out for comparison to the numerical

A two-DOF wrist with three unidirectional drives simulation. Turbulent plumes emanating from line

has been designed to illustrate the principle. sources have been computed using a direct

Actuators and gears are carefully sized to achieve numerical simulation of channel flows. The mean

the isotropic transmission characteristics. scalar field and higher order statistics have been

Driveline flexibility is included in the model as a compared with the physical experiments as well as

primary concern. To make sure that backlash has a series of computations we have performed using

been eliminated, reaction forces in the meshing turbulent closures and random flight models.

Engineering Research 24 1993
University Of Massachusetts University Of MassachusettsChemical Engineering Department $ 0 Lowell

Goessmann Laboratory 03-A Department of Electrical Engineering $61,753 Amherst, MA 01003-0011 903 Lowell, MA 01854 01-C

91-3 A General Procedure for the Synthesis of Stability and Heat Transfer In Time-Modulated

Process Flowsheets Flows

J. Douglas, M. Malone . Thompson

The goal of this project is to develop systematic This project represents a analyticalexperimental procedures for the synthesis of processes for effort directed toward understanding the processes chemical manufacturing. The current aims are to - generating boundary layer instabilities in timedevelop general procedures for separation modulated flows. In particular temporal systems and multiproduct batch processes. modulations of the basic state by harmonic and

free-stream vorticity is considered. The objectives Douglas (AlChE J, 31, 353, 1985) developed a of this work are to: develop an analytical model for

hierarchical procedure for continuous, development of instability, describe the growth and

single-product processes containing vapor-liquid propagation of unstable disturbances occurring in

mixtures. However, mixtures of vapors, organic the viscous region, investigate the stabilizing liquids, aqueous liquids, and solids are common; influence of steady-flow, examine global and local

fortunately, the material flows entering and leaving instability resulting from modulation of the freethe process, the reactor, and the separation stream near points of mean-flow stagnation, and

systems can be determined with minor extensions categorize results suggestive of possible of the original procedure. The new procedure mechanisms for heat transfer.

isolates vapors using a flash, removes solids in a

filter or centrifuge, and separates the organic from It has been shown that for increasing modulation

aqueous liquids in a decanter. New synthesis amplitude of a two dimensional oscillatory flow

methods have been developed for the solid and undergoes a subcritical transition from the 2- D

liquid recovery systems. The complete procedure Stokes boundary layer to a state where

appears to describe most flowsheets that appear streamwise oriented vortices appear. The

in the literature as well as many new altematives. temporal growth of these streamwise vortices is

the result of the imbalance between the centrifugal Multiproduct batch processes are treated by force and the pressure. The most unstable axial

optimization of costs for raw materials, energy, position along the channel corresponds to the

late production, early production, and investment. ocation where the convex wall curvature is

maximum. For a fixed value of the wall curvature, Simulated annealing has proven effective for instability ensues above the critical value of the (approximate) optimizations in the scheduling, Taylor number. The most unstable of these

design, retrofit, lot-sizing and parts of the process wavenumbers or primary mode persists through synthesis, for processes producing hundreds of amplitude saturation and chaos. It has been found

products in dozens of units. that this mode undergoes successive perioddoubling temporal bifurcations to chaotic motion.

However, if subharmonic spatial wavenumbers are

initially present in the disturbance spatial

bifurcation can also occur.

Engineering Research 25 1993
Massachusetts Institute Of optimization of chemical processes. As the

Technology ,chemical industry is one of the largest consumers

of energy in the US, it is important to find efficient

The Energy Laboratory $122,300 and creative computer-aided design strategies for

Cambridge, MA 02139 03-B developing new manufacturing processes, and

91-3 retrofitting existing plants. Metal Transfer in Gas Metal Arc Welding

T. Eagar, J. Lang The general philosophy of this research is to

develop, in an university environment, innovative The objective of this project is to find new control generic methodologies for solving problems of

methods to improve metal transfer in gas metal industrial importance. These methods are then

arc welding - a widely used manufacturing demonstrated by using prototype software to solve

process. A lumped-parameter mathematical problems typical of those encountered in industry. model of the system is being developed with the

goals of being suitable for real-time control system Research is currently considering two topics. A

design, yielding additional physical understanding, long term program that focuses on synthesis and being readily usable by researchers and techniques for achieving increased energy

engineers. efficiency through better heat and work integration

is culminating with an investigation of the A novel gas metal arc welding experiment, which simultaneous synthesis and optimization of the

modifies the fundamental way metal is transferred chemical process, its heat exchange network, and

in the welding process, has been designed and the utility system. Secondly, a new initiative is

constructed. The experiment uses mechanical addressing the need for process design and

energy as a new control input to the welding optimization technologies for

process. The metal electrode is vibrated axially batch/semi-continuous processes. Such processes during welding at the desired frequency of drop are of increasing industrial importance for the

detachment in order to force the detachment of manufacture of high-value added specialty

metal drops. The experiment is being used to products and pharmaceuticals, which have

explore new modes of metal transfer and for relatively short product life cycles. Research is

testing algorithms for detecting and controlling therefore focusing on the development of

these modes. computer-aided design tools for rapid and efficient

process development. The mathematical model being developed

captures the instantaneous dynamics of drop

detachment. Hitherto, dynamic electrode melting Massachusetts Institute Of

models have only sought to capture the average of

the process. The model being developed in this Technology

project captures the instantaneous geometric Lab for Manufacturing & Product $158,000

evolution of drops melting on the end of an axially Cambridge, MA 02139 03-B

moving electrode. This model also has potential 91-3

uses for droplet systems other than welding. Multivariable Control Of The Gas-Metal Arc

Welding Process

D. Hardt

Massachusetts Institute Of In previous work, a basic approach to the problem Technology of control of welding processes using multivariable

Energy Laboratory $105,000 adaptive control theory was established and a set

Cambridge, MA 02139 03-A of non-stationary process transfer functions for

91-3 both the thermal and geometric aspects of the

Synthesis and Optimization of Integrated process, capturing the non-linear dynamics and

Chemical Processes statics, were developed. In addition, depth L. Evans, P. Barton estimators based on real-time inverse heat transfer

solutions and surface temperature measurements

The goal of this research program is to develop have been developed.

new systematic methods for the synthesis and

Engineering Research 26 1993
However, it has become increasingly apparent frictionally stability. The attainment of absolutely

through the modeling and experiments, that the stable, positive friction-velocity characteristics at

process has insufficient latitude to respond to cryogenic temperatures appears improbable

realistic disturbances in a multivariable fashion. In because of the lack of thermally-activated steadyparticular, the heat and mass transfer processes state shear creep. We are presently investigating:

involved are far too coupled to allow independent 1) a force-based approach to magnet design that

regulation of weld geometry or thermal properties. promotes quench-causing conductor microslips to

Accordingly, process modifications to enhance the occur early in the magnet's charging cycle where

"reachability" of the process, including transverse their consequences are relatively benign; and 2)

and longitudinal high frequency weaving of the the cryotribological behaviors at 77K and 4.2 K of

heat source to vary the input heat distribution, are several metal/metal and other nonpolymeric sliding

being developed. pairs, particularly of several hard, creep-resistant,

chemically inert materials such as: the Group 8

In current work, this problem of three-dimensional nobel metals, high-strength ceramics and recentlyheat distribution control is being generalized using developed sputter-deposited diamond films. Of

both a distributed parameter control theory and a particular interest is the extent to which hardness,

novel heat source design. While many simplistic ductility, and chemical compatibility influence

inverse heat transfer and distributed parameter cryogenic-temperature sliding behavior.

control research efforts have been reported, none

deal with the problem in the face of variable

geometries and high degrees of model uncertainty. Massachusetts Institute Of

Efforts in this area are focused on just such Technology

uncertainties and on realistic geometries. e o ecnc nneen Dept of Mechanical Engineering $196,000

Finally, a new welding process that seeks to Cambridge, MA 02139 01-A

decouple heat and mass transfer by using a 913

stream of superheated filler material to both heat Modeling and Analysis of Surface Cracks

and fill the joint has been developed. This "stream D. Parks, F. McClintock

welding" process relies upon very precise control

of the temperature and flow rate of the metal A methodology for predicting constraint-sensitive

stream. This control is achieved by a novel plane strain ductile fracture in engineering

continuous-flow arc furnace that has a small structures is being developed. At low toughness,

thermal mass, thereby allowing rapid temperature the elastic T-stress and K provide a rigorous and

changes in the filler material. Preliminary tests straightforwardlycalculabletwo-parameterfracture

with this apparatus are now underway. mechanics. Applications include pressurized thermal shock. At loads giving moderate to largescale yielding, a modification to the standard

Massachusetts Institute Of effective crack length formulation accounting for effects of T-stress on plastic zone size gives Technology simple and accurate estimates of J, compliance,

National Magnet Laboratory $91,000 and crack tip constraint based solely on elastic K

Cambridge, MA 02139 01-D and T calibrations. In fully plastic cracking of low

93-2 to moderate strength structural metals, asymptotic

Cryotribology (Low Temperature Friction and elastic-plastic crack tip fields fail to dominate the

Wear) Development of Cryotribological strain over microstructural length scales,

Theories and Application to Cryogenic suggesting the utility of rigid/plastic models. Such

Devices fully plastic cracking is based on limit analysis and

Y. Iwasa a micromechanical model of crack tip opening

angle that is sensitive to constraint and an

To advance our understanding of cryogenic- effective slip angle at the crack tip. The

temperature sliding stability, and thereby to corresponding material constants are being

improve the reliability of superconducting magnets, determined from bending and tension tests of both

we have been examining, experimentally and standard and novel design.

theoretically, the fundamental mechanisms of

Engineering Research 27 1993
All of these models are being incorporated into prevent their percolation through the coarse

line-spring finite elements for surface-cracked matrix. It has been found that separation critically

plates and shells, providing simple and depends on the initial formation of an upward

extraordinarily accurate analysis and simulation of propagating pocket within which segregation

these important engineering flaws. occurs: coarse particles rain down through it while

fines remain fluidized, leaving a fines-free bed of

coarse particles below. Segregation is markedly

Massachusetts Institute Of reduced in the absence of this structure.

Technology - the limiting factor to the speed of segregation

The Energy Laboratory $133,000 and hence fines through-put is the speed of the

Cambridge, MA 02139 01-A leading edge of the pocket. This interfacial speed

91-3 is directly linked with the rate at which coarse

Basic Engineering Sciences of Solids particles can become detached from the above

Comminution binary dense-pack. The present work is

C. Peterson, H. Kytomaa, F. McClintock addressing the mechanics of this process

theoretically and experimentally. Comminution of energy materials is energy

intensive; one of the principal sources of The program aims to develop the theoretical base

inefficiency in many classes of devices is the of understanding for particulate segregation

presence of excessive fines within the coarse phenomena in a variety of configurations to help

medium. The fines cause an unwanted shielding of improve processes in which segregation is either

the coarse medium and impose multiple passes on desired, as it is here, or unwanted, as in mixers for

the feed (e.g. roller tables, ball mills) resulting in example. frictional losses. This study investigates the

mechanics of rapid fines removal to provide design

criteria for a new generation of comminution Massachusetts Institute Of

machines with a significantly elevated Massachusetts Institute Of

comminution efficiency. Technology

Dept of Mechanical Engineering $116,846

It is well known that dense, size distributed Cambridge, MA 02139 01-C

particulate media have a natural tendency to 92-3

segregate in the presence of flow and gravity, Rheological and Flow Characteristics of

although these effects remain poorly characterized Dense Multiphase Slurries Employing a

and are typically viewed as a hindrance. Here, the Bimodal Model

aim is to understand and incorporate these R. Probstein

phenomena to improve comminution efficiency.

Using a cylindrical rotary crusher, the research This research aims to develop a rational

studies particle segregation by means of unsteady theoretical and experimental methodology for the

fluidization. in vertical and near vertical rheological and flow property prediction of

configurations. In the conceptual device, the time dense-phase slurries with particles distributed in

scale of the unsteadiness is the period of rotation. size from submicron to several hundred microns.

The goal is to achieve full separation in minimal The approach models a polydisperse suspension

time to accommodate a large and efficient as inherently bimodal, wherein it is considered to

comminution throughput. be made up of a fine fraction which behaves

colloidally and imparts to the suspension many of

Experiments have been conducted with bidisperse its important rheological and flow characteristics,

mixtures of silica spheres (50-3000 micrometers in and a coarse fraction which behaves as if it were

diameter) in water with impulsively started in a pure liquid with the same viscous behavior as

fluidization. The results of numerous experiments the colloidal suspension and raises the apparent

are summarized with the following observations: viscosity through hydrodynamic interactions. To

describe the behavior of the coarse fraction, a

- segregation of bidisperse mixtures can be viscosity equation based on lubrication concepts

achieved with impulsive fluidization, even for was applied to suspensions of non-colloidal

systems in which the fines are sufficiently large to particles. The equation derived for monodisperse

Engineering Research 28 1993
suspensions was also shown to apply remarkably particle migration occurring in concentrated

well to bidisperse and polydisperse suspensions. suspensions undergoing a flow with a nonuniform

The polymodal particle size was either uniformly or shear rate. These experiments address the issue

log-normally distributed, and the broadest size of how the flow field affects the microstructure of

range was 37-212 microns. The maximum suspensions. In order to understand the local

packing of these suspensions obtained from viscosity in a suspension with such a flow-induced,

viscosity measurements were found to be equal to spatially varying concentration, one must know

the dry random packing of the same particles how the viscosity of a homogeneous suspension

divided by 1.19. This is a new dilatancy factor depends on such variables as solids concentration

likely to be associated with lubrication layers and particle orientation. We employ the technique

between the particles. The viscosity equation was of falling-ball viscometry, using small balls, as a

also used to describe the behavior of bidisperse method to determine the effective viscosity of a

suspensions with a very large particle size ratio. suspension without affecting the original

Here, the bidisperse viscosity was simulated using microstructure significantly. We also obtain data.

the bimodal model. The viscosity equation again from dispersivity experiments in which the detailed

matched well with the simulated data. The fluctuations of a falling ball's velocity indicate the

calculated values of maximum packing fraction noncontinuum nature of the suspension and may

were consistent with the experimental values for lead to more insights into the effects of suspension

smaller size ratios. This lends further support to microstructure on macroscopic properties. Finally,

the validity of the bimodal model. The bimodal we are beginning to perform other experiments in

approach was next applied to the high-shear-limit quiescent suspensions, measuring the slip on a

viscosity of a polydisperse suspension with a size rotating sphere and the pressure drop caused by

range from submicron to 40 microns. The a falling ball (in contrast to the use of conventional

separating particle size that divided the distribution rotational viscometers which impose a macrointo a fine and a coarse fraction was found to be scopic shear on the suspension) in order to learn

1.5 microns. It was determined so as to give the more about the microstructure and boundary

best fit between the bimodal model and effects in concentrated suspensions.

experiment. The result for the separating particle

size showed that the fine fraction is indeed

colloidal. University Of Minnesota

Dept of Aero Eng & Mechanics $205,000

Minneapolis, MN 55455 01-C Massachusetts Inst Of Tech 93-5

Dept of Chemical Engineering $60,855 Lubricated Transport of Viscous Materials

Cambridge, MA 02139 06-C D. Joseph

91-3

Los Alamos National Lab2 The focus of the research is studies of lubricated

MEE-9 S108,000 transport of viscous materials: viscous crude oils,

Los Alamos, NM 87545 06-C concentrated oil/water emulsions, slurries and

\91-3 capsules. We have emphasized problems which

Sandia National Laboratories3 arise in pipeline applications. Four categories of study are underway. The first is the study of the

Division 1512 $98,000 fluid dynamics of core flows emphasizing studies

Albuquerque, NM 87185 06-C of stability and, more recently, problems of start91-3 up, lift-off and eccentric flow when gravity causes

Macrostatistical Hydrodynamics the core flow to stratify. We have also correlated

H. Brenner', A. Grahani, L. Mondy' all the available data on friction factors and holdup for core flow and shown good agreements This research combines theory, experiments and b n el and k - E models in

numerical calculations to focus on slow flows of turbulent flow

suspensions in which colloidal and inertial effects

are negligibly small (Macrostatistical Hydrody- A second category of studies treats the problem of

namics). We conduct nuclear magnetic resonance fouling of pipe walls with oil, with undesirable

imaging experiments to quantitatively measure increases in pressure gradients and even flocking.

Engineering Research 29 1993
We propose to do the first studies of rates of The submicron TiO2 powder synthesis required

fouling as they depend on the parameters of several apparatus modifications-for maximizing the

lubricated pipelining together with remedial rutile phase in the product. At present, we are

strategies based on the manipulation of the modeling the temperature and species distribution

materials of wall construction. The remedial in an induction plasma reactor for optimization of

strategies may go a long way in relieving the main the reactor design for obtaining a single phase

problems impeding lubricated pipeline technology. product.

The third category is to gain an understanding of

the mechanisms of flow-induced migration of National Academy of Sciences/

particles leading to lubricated configurations. For National Research Council

this, we do direct numerical simulations in which

the particles are moved according to their Washington, DC 20418 $1,064,701

equations of motion by hydrodynamic forces 06-C

computed exactly. One goal of this study is to see Department of Energy Integrated 92-3

if lift forces proportional to the square of the Manufacturing Fellowship Program

velocity are strongly involved in fast flow of B. Kuhn

slurries, capsules and oils. Twelve three-year predoctoral fellowships in

The fourth category of problems is the lubricated integrated manufacturing have been awarded by

transport of concentrated oil/water emulsions. the National Research Council, under the aegis of

the National Academy of Engineering following a

national competition. The winners were selected

University Of Minnesota from a pool of 144 applicants by a panel of 15 univer~sity Vl lnnesoi~ a ~engineering scholars and industrial experts. The

Dept of Mechanical Engineering $141,904 objective of the program is to create a pool of

Minneapolis, MN 55455 06-C PhD's trained in the integrated approach to

92-4 manufacturing, to promote academic interest in the

Thermal Plasma Processing of Materials field, and to attract talented professionals to this

E. Pfender, J. Heberlein challenging area of engineering.

The objective of this research project is to study The fellowship program was conceived as one

analytically and experimentally specific thermal response for the loss of competitiveness of the

plasma processes for materials treatment. United States in manufacturing. Recent studies of

Processes of interest include the synthesis of manufacturing in the United States showed a need

ultrafine ceramic powders and of diamond films. for a more integrated approach to manufacturing

than that prevailing in industry today. Two related

During the past year, we have concentrated on (a) aspects of the problem are the traditional

characterizing the deposition process of diamond separation of the product design function from the

films over larger areas, and (b) studying the TiO2 manufacturing function and the lack of an

submicron powder synthesis process appreciation for the process of manufacturing as

experimentally and theoretically. an integrated system.

The deposition of diamond films over a larger area It is expected that the improved manufacturing

required tailoring the substrate cooling such that a methods which this fellowship aims to bring about

uniform substrate temperature was obtained in will contribute to improved energy efficiency, to

spite of strongly non-uniform heating by the better utilization of scarce resources, and to less

plasma jet. Modeling of the heat flux distribution degradation of the environment.

in the substrate holder led to specific substrate

holder designs resulting in a temperature variation

of only +/-20°C over a 50 mm diameter substrate,

and a uniform film growth over this region at

growth rates of 200 prn/hr.

Engineering Research 30 1993
National Center for National Institute Of Standards

Manufacturing Sciences & Technology

Technology Sourcing $45,500 Thermophysics Division $551,000

Ann Arbor, Ml 48108 06-C Gaithersburg, MD 20899 03-B

93-2 Boulder, CO 80303 91-5

Industrial Liaison Pilot Program

J. Sheridan Development of Measurement Capabilities for

the Thermophysical Properties of EnergyThe National Center for Manufacturing Sciences Related Fluids

has been funded by DOE, Basic Energy Sciences, R. Kayser, J. Levelt Sengers, M. Moldover, W.

to direct a program which will place employees of Haynes

the National Laboratories at industrial sites to work

with their corporate colleagues on issues of The major objectives of this project are to develop

importance to manufacturing industry. The goals state-of-the-art experimental apparatus that can be

of the program are to evolve expertise in a broad used to measure the thermophysical properties of

range of manufacturing issues at the National a wide range of fluids and fluid mixtures important

laboratories, identify fundamental DOE research to the energy, chemical, and energy-related

needs, and build a long-range sustained industries and to carry out carefully selected

commitment to collaboration on industrial issues benchmark measurements on key systems. The

both at DOE and within industry. Results from the specific measurement capabilities completed

Liaison Program will strengthen industry's energy (denoted by asterisk) or under development

efficiency in its operations by enhancing the quality include new apparatus for transport properties

of the total product and developing efficient (tantalum-hot-wire thermal-conductivity apparatus',

production and management techniques. This will vibrating-wire viscometer), thermodynamic

directly benefit American manufacturing properties (dual-sinker densimeter, highcompetitiveness and will help DOE Basic Energy temperature vibrating-tube densimeter, totalSciences identify fundamental research needs in enthalpy flow calorimeter), phase equilibria

energy efficient industrial methodologies and properties (recirculating phase equilibria

technologies. apparatus, low and high-pressure ebulliometers',

re-entrant radio-frequency resonator), and

A pilot program will be conducted to immediately dielectric properties (concentric-cylinder dielectricplace a limited number of workers and carefully constant apparatus'). These new apparatus will

evaluate the effectiveness of a sustained program. extend significantly the existing state of the art for

The pilot program is important. There are a properties measurements and make it possible to

number of potential risks and blockers which need study a wide range of complex fluid systems (e.g.,

to be assessed carefully before a large highly polar, electrically conducting, and reactive

commitment is made. The Industrial Liaison fluids) under conditions which have been

Program (ILP) will place DOE laboratory workers previously inaccessible. This project also includes

into the industrial environment to focus the benchmark experimental measurements on

attention of the laboratories on industry issues. alternative refrigerants and refrigerant mixtures

The worker will remain a full time employee of the (completed and ongoing), aqueous solutions, and

Laboratory but the costs of the off-site per diem carefully selected systems consisting of species of

will be shared by the host company through a diverse size (methane + neopentane) and polarity

formula-based reimbursement. (methane + ammonia) that are important to the

development of predictive models for energyrelated fluids.

Engineering Research 31 1993
National Institute Of Standards low and from regions of high particle

& Technology concentrations to low which, by distorting the

particle concentration profile, can lead to an

Electromagnetic Technology Div $ 0 erroneous interpretation of the experimental

Boulder, CO 80303 06-C measurements. This shear-induced particle

89-3 diffusion is also responsible for the phenomenon

Low Resistivity Ohmic Contacts Between of viscous resuspension whereby in the presence

Semiconductors and High-Tc of shear flow, a settled bed of heavy particles can

Superconductors resuspend even under conditions of vanishingly

J. Moreland, J. Ekin small Reynolds numbers.

The purpose of this project is to fabricate and Viscous resuspension was studied both

characterize contacts between high-T, theoretically and experimentally in various

superconductors (HTS) and semiconductors. unidirectional flows, e.g. a 2-D Hagen-Poiseuille

Developing a method for optimizing the current flow, as well as a Taylor-Couette system, and

capacity of such contacts will extend the excellent agreement has been found to-date

application of HTS materials to semiconductor between the experimental results and the

hybrid technologies that have HTS interconnects theoretical predictions even though the latter do

(both on-chip and package) and proximity HTS/ not entail the use of adjustable parameters. In

semiconductor/HTS SNS Josephson Junctions. addition, the stability of the resulting stratified twoPresently, these are some of the most promising phase flows was investigated theoretically on the

HTS applications, but an essential first step is the basis of a small disturbance stability analysis, and

development of stable ohmic contacts between again good agreement was found between the

semiconductors and HTS materials. theoretically predicted conditions for the onset of

growing disturbances and experimental The project is now focused on YB2Cu3O, (YBCO) observations regarding the appearance of

thin-films grown on Si wafers. Recent discoveries interfacial waves.

have shown that it is possible to grow high quality

HTS films on Si using laser ablation deposition

and a yttria stabilized zirconia buffer layer between The City University Of New York

the YBCO film and the Si. Processing steps are e Ciy ersiye

being optimized for depositing and patterning The City College $126,528

YBCO films on Si to form contact vias to the Si Department of Chemical Engineering 03-A

substrate. The goal is to minimize the specific New York, NY 10031 91-3

resistance of the contacts using techniques that

are compatible with standard Si processing. Partial Control of Complex Processing Systems

R. Shinnar, I. Rinard

The City University Of New York There are two research objectives. One is to

The City College $89,804 understand the control of Fluidized Catalytic

The Benjamin Levich Institute 06-C Crackers (FCC's), an important goal in itself due to

for Physico-Chemical Hydrodynamics 90-3 the central role played by FCC's in modem

New York, NY 10031 refineries. The second is to use the FCC as an

example to learn about the control of complex The Rheology of Concentrated Suspensions chemical plants. The FCC control problem is rich

A. Acrivos enough to contain many of the nonlinear features

found in such plants. This research program aims to investigate the flow

of concentrated suspensions of non-colloidal A dynamic simulation model of the FCC has been

particles from the fundamental point of view. developed for these studies. It is based on a

Earlier studies by the Principal Investigator and his recently published model but contains many

associates have shown that the rheology of such enhancements which insure that its behavior is

systems is strongly affected by the shear-induced representative of current FCC operation.

migration of particles from regions of high shear to

Engineering Research 32 1993
The work has demonstrated that the performance Northwestern University

of FCC's in the region of current operation exhibits Engineering & Applied Science $89,450

five multiple steady-slates as well as input Evanston, IL 60208 03-B

multiplicities of some of the important 93-3

manipulatable variables. This size of the region of Thin-Film Characterization and Flow

five steady-states can be greatly reduced by the Detection

use of a combustion promoter. This helps explain J Achenbach

why the use of a promoter is so popular in the

industry even though its use has little economic This work is concerned with the determination of

benefit other than better controllability. the elastic constants of thin films deposited on

substrates, with the measurement of residual

stresses in such films and with the detection and

The City University Of New York characterization of defects in thin film substrate

The City College $102,500 configurations.

The Benjamin Levich Institute 06-C

of Physico-Chemical Hydrodynamics 91-3 There are many present and potential applications

New York, NY 10031 of configurations consisting of a thin film deposited

on a substrate. Thin films that are deposited to

Studies in Premixed Combustion improve the hardness and/or the thermal

G. Sivashinsky properties of surfaces are of principal interest in

this work. Thin film technology does, however,

The objective of this research is a combined also include high Tc superconductor films, films for

analytical and numerical study of the influence of magnetic recording, superlattices and films for

various hydrodynamic, thermal-diffusive and band-gap engineering and quantum devices. The

reaction rate factors on speed, shape, stability and studies carried out on this project also have

the extinction limits of premixed gas flames. relevance to these applications.

Different modelling techniques will be employed to

reduce the study of the pertinent combustion Both the film and the substrate are generally

systems to simple approximate problems tractable anisotropic. A line-focus acoustic microscope, is

either analytically or numerically. Specifically, the being used to measure the speed of surface

project is concerned with (1) the dynamics of acoustic waves (SAW) in the thin film/substrate

premixed flames spreading through a one- and system. This microscope has unique advantages

multiple-scale system of eddies and with the for measurements in anisotropic media. Analytical

further development and refinement of the and numerical techniques are employed to extract

associated cascade-renormalization concept of the desired information on the thin film from the

turbulent flame speed; (2) the intrinsic dynamics measured SAW data. Recent results include: (1)

and the pattern formation in premixed flames analytical and numerical techniques for the direct

sustained by the thermal-diffusive and thermal problem and the inverse method, (2)

expansion induced mechanisms of flame measurements of superlattice film constants, (3)

instability; (3) the hydrodynamical aspects of investigation of the effect of surface roughness

combustion limits with particular attention to the and (4) measurements of residual stresses in thin

phenomena of flame extinction by one- and films.

multiple-scale periodic flow fields and extinction in

upward and downward propagation flames in

tubes; and (4) the development of new numerical

methods especially assigned for the free-boundary

problems of flame-flow interaction and

spontaneous pattern formation in premixed flames.

Engineering Research 33 1993
Northwestern University Northwestern University

Dept of Chemical Engineering $235,036 Dept of Eng Sci & App Math $53,000

Evanston, IL 60208 01-B Evanston, IL 60208 01-C

92-3 91-3

Stability and Rupture of Thin Fluid Films on Effects of Capillarity of Macroscopic Flow in

Heated Solids Surfaces Porous Media

S. Bankoff, S. Davis M. Miksis

The objective of this work continues to be the The objective of this project is to study the effects

study of the dynamics, stability and rupture of thin of capillarity on the motion of a fluid in a porous

liquid films, especially with heat and/or mass material. The primary concern will be the

transfer. These films appear in many engineering micromechanics of the fluid motion when

processes, such as film coating, gas absorption, interfaces are present and its effect on the

condensation, and especially cooling of hot macroscopic flow. These interfaces could exist as

surfaces. The analysis has been extended to a liquid moves into an unsaturated porous material

stratified flow of two thin incompressible, or when there are two phases within the porous

immiscible layers between stationary parallel walls, material; e.g., liquid/gas or liquid/liquid. Attention

subject to body forces and surface tension. A will be directed to understanding and modeling the

long-wave generalized evolution equation of the dynamics of these interfaces and then relating

Benney type is derived, which reduces for special their dynamics to the macroscopic behavior of the

cases to previously derived results. Upon material.

linearization, four different stability diagrams are

found in wavenumber/flow rate space, Part of our attention is directed to foam flow in

representing the competition of different physical porous media. A foam is generated when, for

effects. A small-amplitude analysis yields an example, a gas is injected into a fluid saturated

extended Kuramoto-Sivashinsky (KS) equation porous media. We have studied this generation

containing both quadratic and cubic nonlinearities. process by considering the dynamics of a gas

It is found that the symmetry-breaking bifurcation bubble as it is driven past a constriction; e.g., in a

of the KS equation is now imperfect. Modulated capillary tube. Here we have observed that under

travelling waves of large amplitude may bifurcate certain conditions, the bubble snaps into two parts;

from the traveling wave solutions, and hysteresis hence forming the building blocks of a foam.

loops may be formed, which may be pertinent to These new smaller bubbles are separated by a

the flooding phenomenon in countercurrent parallel thin liquid film, a lamella, which controls the

flows. stability of the foam. The stability of this lamella

has also been studied.

The experimental program is designed to confirm

the range of validity of the theoretical analysis, and

to determine its practical limits. By operation Northwestern University

under conditions of extreme quiet, the classical Dept of Chemical Engineering $111,422

linear stability theory for long waves on a falling Evanston, IL 602083120 06-C

film was fully confirmed for the first time. A mirror 91-3

system allows a complete 360° view of the tube to Mixing of Immiscible Fluids in Chaotic Flows

be obtained in a single frame. This allows the and Related Issues

measurement, using image digitization, of the J. Ottino

development of circumferential secondary waves

from the primary ring waves. As predicted, this The goal of our work is to provide a general

development is rapid when the tube is heated, understanding of the mixing of viscous fluids. The

owing to thermocapillary effects. problem is of importance in the chemical and

processing industries. We have nearly completed A numerical investigation is under way to examine he original objectives under this grant and we are the original objectives under this grant and we are nonlinear spatially growing or decaying waves on now actively engaged in pursuing avenues

a falling film. suggested in the course of our investigation. We

Engineering Research 34 1993
have completed our studies of stretching, breakup, incorporates an additional slow time-scale due to

and dispersion of viscous droplets in chaotic flows. the slowness of mass diffusion. The derivation will

As a result of these studies we developed a be considered for more realistic conditions. The

method to measure the interface between two velocity of the waves will be calculated in a

liquids based on the complete surface tension- perturbation around the soliton. The effect on

driven time evolution of a stretched filament, plane waves will be investigated.

including satellite and sub-satellite formations, in

terms of Boundary Integral Equation Methods. In addition, localized structures in the form of

Two important extensions are also being pursued: domain walls will be studied. Arrays of such walls

Mixing of non-Newtonian fluids and chaos- are related to zig-zag structures as found in

enhanced transport. The non-Newtonian area isotropic and anisotropic convection.

consists of two sub-projects: (i) mixing of

viscoelastic fluids (Boger fluids), and (ii) mixing of

shear thinning fluids. Area (i) involves both University Of Notre Dame

experiments and computations whereas (ii) is Department of Chemical Engineering $60,246

exclusively computational. The chaos-enhanced Notre Dame, IN 46556 01-C

transport focuses on transport to and from cavities, 92-3

the flow within the cavity being modulated by a Wave Dynamics on Falling Films and Its

wavy flow and the cavity itself possessing, Effects on Heat/Mass Transfer

possibly, a multicellular structure. These two last H-C. Chang

areas will comprise the bulk of our efforts for the

next year and beyond. Wave formation on a falling liquid film can be a

desirable phenomenon since the waves enhance

interphase heat or mass transfer in many industrial

Northwestern University gas-effluent cleaning devices (scrubbers) and in

Dept of Eng Sci & App Math $68,058 some solar energy collectors. In paper and optical

Evanston, IL 60208 06-C fiber coating processes, however, waves tend to

92-3 reduce the coating quality and lower the

Stability and Dynamics of Spatio-Temporal production rate. This project is to investigate how

Structures the waves are formed, how they can be removed

H. Riecke and how they can enhance heat/mass transfer.

Our approach is to combine theoretical techniques

This research will be concerned with a study of from Dynamical Systems theory, numerical

physical systems which exhibit a transition from a simulation, and experiments to achieve these

homogeneous state to a spatial and/or temporal goals. With the first two techniques, we have

structure when driven sufficiently far from been able to understand the primary, secondary

thermodynamic equilibrium. Such non-equilibrium and tertiary transitions of waves from nearly

structures are found, for instance, in fluid sinusoidal waves at the inlet to the solitary waves

dynamics - Rayleigh-Benard convection and Taylor downstream. It is the only hydrodynamic instability

vortex flow -- and in solidification -- Mullins- that is understood beyond the primary inception.

Sekerka instability. They also serve as paradigms Our nonlinear analysis allows us to associate drop

for non-equilibrium structures in general which formation during fiber coating to a blow-up

arise in other fields such as chemistry and solution. We are currently developing the wavelet

mechanics. numerical method for wave evolution, finalizing an

experiment for falling film and using

Specifically, the research focusses on localized renormalization group theory to predict interphase

waves observed in binary-mixture convection, transfer from the predicted wave spectra.

They have been described theoretically as Feedback control to stabilize the waves will soon

dissipatively perturbed soliton solutions of the be attempted.

complex Ginzburg-Landau equations. However, it

has been found that the resulting predictions

qualitatively disagree with certain aspects of the

observations. The present work will build on an

extension of these equations derived earlier, which

Engineering Research 35 1993
University Of Notre Dame perform a variety of tasks in incompletely known

Department of Chemical Engineering $54,000 environments, given only qualitatively specified

Notre Dame, IN 46556 01-C goals. The Center provides a focal point for

91-3 interdisciplinary research in machine intelligence,

Study of Interfacial Behavior in Cocurrent cognitive systems, advanced control, and systems

Gas-Liquid Flows engineering. Research objectives are chosen to

M. McCready address the technology-base requirements for

DOE missions that rely on the use of robotics and

The objectives of this work are to develop a intelligent machines. In particular, research

mechanistic and mathematical understanding of concentrates on issues related to autonomous

various types of small-scale (e.g., waves) and systems, unstructured dynamic work

large scale (e.g., slugs) disturbances that are environments, and multiple cooperating robotic

observed in cocurrent gas-liquid flows. systems. Results from CESAR research in

automation-related technologies and intelligent

Measurements of wave properties (e.g., speed, machines can increase productivity and safety in

wavelength, amplitude and rates of evolution) are the development and operations of DOEused to verify linear and nonlinear theoretical sponsored systems. Potential and actual

approaches that are based on simplifications of applications include emergency situations, remote

the Navier-Stokes equations. Most of this work is operations, resource exploration, transportation

done at conditions close to neutral stability where systems, advanced power generation systems,

definite comparisons of theory and experiments and environmental restoration and waste

are possible. management.

Currently, several important secondary wave CESAR is intended to be a national resource, and

transitions are being studied. These are:(1) a major objective is to disseminate R&D

formation of waves with twice the wavelength of accomplishments freely and comprehensively.

the fundamental (i.e., subharmonics); (2) initiation Results and technology advancements are

of very long wavelength modes that can grow into distributed through publications in the scientific

roll waves or slugs; (3) formation of transverse literature, through organization of workshops on

modes which lead to greater dissipation and a selected topics, and through the development of

degree of stabilization of the flow. It is found that prototype systems that demonstrate concepts and

weakly-nonlinear theory gives insight into these new methodologies. CESAR cooperates with

secondary transition mechanisms that cannot be universities, laboratories and industry, serving as

understood using only linear theory. An additional a collaborative research facility to provide guests

topic of current interest is determination of the with access to state-of-the-art and often unique

features of turbulence that must be incorporated equipment in a stimulating research environment.

into linear and nonlinear theories to accurately

describe the generation and evolution of waves. Ohio State University

Physics Department $69,000

Oak Ridge National Laboratory Columbus, OH 43210 06-C

Engineering Physics $1,250,000 91-3

and Mathematics Division 03-C Turbulence and Spatio-Temporal Chaos

Oak Ridge, TN 37831 87-5 C. Jayaprakash, F. Hayot

Center for Engineering Systems Advanced This program deals with the dynamics of extended

Research (CESAR) (with many degrees of freedom), dissipative, nonR. Mann, F. P linear systems.

The Center for Engineering Systems Advanced An important issue in this area concerns the

Research [CESAR] is established at Oak Ridge existence of effective stochastic equations to

National Laboratory to address long-range, describe the long wavelength properties of partial

energy-related research in intelligent machine differential equations that exhibit deterministic

systems. These systems are intended to plan and chaos. We are currently studying the KuramotoEngineering Research 36 1993
Sivashinsky (K-S) equation and its variants. This Within certain classes of initial conditions, the first

is done numerically(using spectral codes) by step in our approach consists of imbedding the

explicit elimination of short wavelength modes with ill-posed time evolving problem at zero surface

an emphasis on interpreting the physical basis of tension (or zero regularization in a wider context)

the parameters in the effective equations. For the as part of a well-posed problem at the expense of

K-S equation in one and two spatial dimensions, studying the initial value problem in the unphysical

the effective equation is the Kardar-Parisi-Zhang complex plane. This has been done without

equation that is a generic model for stochastic resort to any approximations by introduction of a

growth of interfaces although the crossover length novel numerical method.

scale beyond which this applies is very large. We

have also been studying the complex Ginzburg- Small regularization effects have been introduced

Landau equations from this point of view. in a perturbative manner in the extended domain

for many cases. This removes the sensitivity of

Extensive numerical simulations of coupled map the dynamics to initial conditions when posed in

lattice models and resistively shunted junction the complex domain. In our next phase, we will

models of Josephson junction array's are being also look into dynamics of random initial

carried out to elucidate features of spatio-temporal singularities in order to connect with statistics of

chaos in extended systems. We have found that nonlinear noise amplification.

these systems exhibit non-Gaussian probability

distribution functions for local variables, a

phenomenon that occurs in fluid systems. This Oregon State University

has led us to suggest a new mechanism for such Dept of Mechanical Engineering $102,142

behavior. Corvallis, OR 97331-6001 01-B

91-3 A focus of current research in the field is generic Radiative Transfer Through an Array of

scale invariance (algebraic decay of spatial Discrete Surfaces

correlations without tuning external parameters). J Welty

The aims of projects underway include

understanding how a conserved mode can induce This project involves experimental measurement

scale invariance in non-conserved modes, and and characterization of radiative transfer through

elucidating different mechanisms that can lead to arrays of fixed discrete surfaces. It is being

generic scale invariance by studying model carried out in cooperation with Battelle Pacific

systems. Northwest Laboratory.

The aim of this research is directed at identifying Ohio State University basic relationships between array geometry

Mathematics Department $66,143 (spacing, packing arrangement, and element

Columbus, OH 43210 06-C shapes), surface properties, and radiative transfer

92-3 through a two-dimensional array. The information

The Evolution of a Hele-Shaw Interface and resulting from this study may also be useful in

Related Problems in Dendritic Crystal Growth establishing criteria for the valid application of

S. Tanveer participating media models to arrays of fixed

discrete surfaces.

The ultimate objective is the prediction of

complicated noisy time evolving features that are Accomplishments to date include the following: (1)

observed in Hele-Shaw experiments or in a the design, construction and operation of a

dendrite growing in an undercooled liquid for small bidirectional reflectometer, (2) measurements of

capillarity. From a mathematical perspective, we bidirectional reflectances of several materials, (3)

like to calculate the effect of a small regularization demonstration of the need for full BRDF

(capillary effects) to regularize an otherwise (bidirectional reflectance distribution function)

ill-posed problem. Such problems are information for striated surfaces, and (4)

characterized by the appearance of disparate installation and operation of an enhanced Monte

scales both in space and time which make a direct Carlo code.

numerical calculation very difficult.

Engineering Research 37 1993
The reflectometer possesses flexibility of use and FY 1993 accomplishments consist of: 1) the Monte

precision which are superior to any similar devices Carlo code has been completed and validated

described in the literature. The need for such an against other Monte Carlo results, 2) simulation of

instrument stems from the direct dependence of a range of array geometries showed, that radiation

Monte Carlo results on the accuracy of surface heat transfer in most arrays of practical interest

property information. Measurements have been can not be predicted solely on the scattering

taken for several materials possessing varying properties of an individual element but, also

degrees of diffuse and specular reflecting depend on the geometric arrangement of the

characteristics. elements. Accurate modeling of radiation heat

transfer in arrays will, in most cases, require that

A common assumption made, in analyzing radiant the array is modeled as discrete surfaces rather

heat transfer among surfaces, is that the then as a homogeneous media, 3) parametric

reflectance is independent of the azimuthal angle studies have shown that the inclusion of polarity in

of the incident beam. Measurements of BRDF for Monte Carlo modeling can have a significant effect

striated surfaces indicate that, for a broad class of on the results of the Monte Carlo simulations and

surfaces, this assumption can lead to significant needs to be considered by other researchers, and

error. Our instrument has the capability for 4) one technical paper was published in FY 93

complete surface property description which will and two journal articles were submitted to journals

allow Monte Carlo simulation of surface arrays to for publication in 1993.

be made without the inherent errors resulting from

the azimuthal angle assumption.

University Of Pennsylvania

Mechanical Engineering Dept $101,400 Pacific Northwest Laboratory Philadelphia, PA 19104 01-C

Battelle Memorial Institute $104,000 92-3

Richland, WA 99352 01-B Active Control of Convection

91-3 H. Bau

Radiative Transfer Through Arrays of

Discrete Surfaces with Fixed Orientation Active, feedback control strategies to alter the

M. Drost structure of convection in a fluid layer heated from

below and cooled from above (the RayleighRadiative heat transfer in an array of discrete Benard problem) are studied experimentally and

surfaces, is an important and poorly understood theoretically. The objectives are to (i) stabilize the

class of radiative heat transfer problems. The no-motion state of Rayleigh-Benard convection

objective of this study is to develop an (delay to higher values of the Rayleigh number the

understanding of the impact of array geometry, transition from the no-motion to the motion state);

surface properties, and incident radiation and (ii) suppress (laminarize) oscillatory, chaotic

characteristics on radiation heat transfer in the convection. This work is a continuation of an effort

array. The results of the study will be used to in which it was successfully demonstrated that

establish criteria for the valid application of feedback control can be used in a thermal

participating media models to arrays of fixed convection loop to tame chaos. The results of this

discrete surfaces. work may be of importance, among other things,

to materials processing and crystal growth

The approach consists of using an innovative applications in which it is desirable to eliminate

Monte Carlo model to evaluate radiation heat convective currents or suppress oscillatory

transfer in arrays of fixed discrete surfaces with a convection. What is learned during this research

range of array configurations. The Monte Carlo may also be useful for devising control strategies

model will be validated by comparison with for other non-linear flow phenomena. Thus far, it

experimental results being developed at Oregon has been theoretically demonstrated that, with the

State University. The Monte Carlo simulations will aid of a feedback controller, the transition from the

be used as a benchmark for comparisons with no-motion to the motion state can be significantly

different analytical approaches that model the delayed. An apparatus for experimental

array as a participating medium.

Engineering Research 38 1993
verification of theoretical predictions is under Physical Sciences Inc.

construction and a computer code to study time- 20 New England Business Center $130,000

dependent flows is under development. Andover, MA 01810 06-A

92-4

Experimental and Theoretical Studies of

Pennsylvania State University Multicomponent Vapor Condensation

Mechanical Engineering Dept $95,793 G. Wilemski, B. Wyslouzil

University Park, PA 16802 06-B

92-3 This research program comprises experimental

Experiments on the Gas Dynamics of the and theoretical studies of nucleation and

HVOF Thermal Spray Process condensation in m ulticomponent gas mixtures. The

G. Settles program goals are: (1) to improve basic

understanding of nucleation and droplet growth,

High Velocity Oxy-Fuel (HVOF) thermal spray (2) to stringently test theories of nucleation at high

technology has grown in a decade to become nucleation rates and under nonisothermal

second only to plasma spraying in the application conditions, (3) to develop improved theories where

of metallic coatings. HVOF coatings have needed, (4) to enlarge the data base for systems

desirable high densities and other potential of both fundamental and practical interest, and (5)

advantages of economy and simplicity. to provide reliable means for predicting the

behavior of mixtures in practical devices and in the

Because HVOF uses high-speed gaseous atmosphere. Condensible vapors, mixed with a

combustion products to heat and accelerate metal carrier gas, are cooled in a supersonic Laval

particles, the gas dynamics of the process exerts nozzle to obtain high nucleation rates under

a profound influence on its performance. steady state conditions. Interferometry and laser

However, commercial HVOF equipment has yet to light scattering are used to detect the "onset" of

exploit this potential. The objective of this research condensation and to monitor subsequent droplet

is to conduct experiments and modeling of HVOF growth. Theoretical calculations of the droplet size

gas dynamics, thus to improve the process. distribution along the flow axis are performed to

assess competing theories of nucleation and

Schlieren visualizations reveal that the supersonic droplet growth. A new experimental apparatus is

HVOF jet undergoes very rapid turbulent mixing also being constructed to study binary nucleation

with the atmosphere. Planned experiments will in mixtures of sulfuric acid and water vapor

examine and attempt to reduce this mixing, using

analysis of the oxide content of sprayed coatings Recent nozzle experiments with a fixed water or

as a measure of success. Analysis and ethanol vapor pressure reveal a small increase in

experiments are also being performed to optimize the onset temperature of condensation that

the design and operation of the supersonic HVOF accompanies a decrease in the carrier gas

spray nozzle. The heat and momentum transfer stagnation pressure from 3 to 0.5 atm. This effect

between the gas and sprayed particles are also can be quantitatively explained by the changes

being examined. that occur in the boundary layer displacement

thickness and the heat capacity of the flowing gas

Ultimately, an improved HVOF apparatus at different pressures. The results provide no

embodying gas-dynamic principles will be evidence for the role of energy transfer limitations

designed and tested. Technology transfer from on nucleation under conditions of excess carrier

rocket propulsion and supersonic aerodynamics is gas in the atmospheric pressure range. Other

a key element of this project. recent experimental and theoretical studies of

ethanol condensation have shown that the relative

importance of nucleation and droplet growth at

onset changes dramatically depending on the

Engineering Research 39 1993
magnitude of the nucleation rate achievable for shows that the average flame speed increases

different experimental conditions. Under with either increasing fluctuation amplitude or

conditions yielding lower nucleation rates in the increasing wavelength of the imposed flow, that

nozzle, the condensate mass occurs the flame surface can locally extinguish for

overwhelmingly as large (5-25 nm radius) sufficiently large fluctuation amplitudes of the

supercritical droplets. This indicates that droplet imposed flow, and that the structure of the flame

growth and nucleation are concurrent processes cusps resembles that of the Bunsen flame.

under these conditions. As the temperature and

ethanol vapor pressure are lowered, increasingly

higher nucleation rates are attained at onset, and Princeton University

the mass of condensate occurs predominantly as Dept of Civil Engineering $205,892

small (0.5-1 nm radius) nearly critical droplets. Princeton, NJ 08544 06-A

Under these conditions droplet growth contributes 93-4

substantially to the accumulation of condensate Transport Properties Of Disordered Porous

only after nucleation has subsided. Media From The Microstructure

S. Torquato

Princeton University This research program is concerned with the

Dept of Mech & Aero Eng $96,000 quantitative relationship between transport

Princeton, NJ 08544 06-B properties of a disordered heterogeneous medium

93-3 that arise in various energy-related problems (e.g.,

Mechanisms and Enhancements of Flame thermal or electrical conductivity, trapping rate,

Stabilization and the fluid permeability) and its microstructure.

C. Law In particular, we shall focus our attention on

studying the effect of: porosity, spatial distribution

The program aims to gain fundamental of the phase elements, interfacial surface

understanding of the structure and stabilization statistics, anisotropy, and size distribution of the

mechanisms of premixed and nonpremixed flames phase elements, on the effective properties of

through theoretical and experimental models of both unconsolidated media (e.g., soils

investigations. The following major projects were and packed beds of discrete particles) and

completed during the reporting period. consolidated media (e.g., sandstones and sintered

materials).

A comprehensive study has been conducted for

the structure of the adiabatic, equidiffusive, and Both theoretical and computer-simulation

freely-propagating premixed methane/air flame techniques have been employed to quantitatively

situated in a counter flow. The velocity, characterize the microstructure and compute the

temperature, and major species concentration transport properties of disordered media.

profiles were experimentally mapped through Statistical-mechanical theory has been used to

laser-based instrumentation and computationally obtain n-point distribution functions and to study

determined with detailed reaction mechanisms and percolation phenomena in continuum

transport properties. These results agree closely random-media models. For example, the porewith each other, and demonstrate that the size distribution, lineal path function, and the

structure of such flames remain basically invariant chord-length distribution function have ben

to strain rate variations. The results are of investigated and computed. This has led to

relevance to the modelling of turbulent flames. accurate predictions of transport properties of

realistic models of isotropic as well as anisotropic

The geometry and dynamics of stretched, wrinkled heterogeneous media. An efficient Brownian

flames have also been analytically studied. The motion computer-simulation methodology has been

analysis successfully describes the geometry of employed to yield exactly effective diffusion

the experimentally-observed configuration of the parameters for a host of useful models. Rigorous

Bunsen flame tip at the state of opening, and relations which link the fluid permeability to length

demonstrates that the flame temperature and scales obtainable from Nuclear Magnetic

flame speed remain finite at such a state. Resonance experiments and the effective electrical

Analysis of flame propagation in periodic flows conductivity have been derived.

Engineering Research 40 1993
Purdue University area, fluid particle size and their axial development

School of Mechanical Engineering $92,888 from the entrance to the exit will be the primary

West Lafayette, IN 47907 01-C focal point of the research. For the purpose of

93-3 understanding the dynamic behaviors of the

Effect of Forced and Natural Convection on interfacial velocity, wave characteristics, fluid

Solidification of Binary Mixtures particle coalescence and disintegration. These will

F. Incropera be characterized by the collision frequency, interfacial energy and turbulence dissipation in

This study deals with the influence of combined liquid.

convection mechanisms on the solidification of

binary systems. A major accomplishment of The five-sensor resistivity probe is developed for

research performed to date has been the the measurement of the local interfacial area, void

development and numerical solution of a fraction and three-dimensional components of

continuum model, which uses a single set of interfacial velocity. This five-sensor probe is

equations to predict transport phenomena in the intended to be used for general two-phase flow

liquid, "mushy" (two-phase), and solid regions of except annular flow. By combining the capability

the mixture. Calculations have been performed for of a double-sensor probe for the measurement of

aqueous salt solutions and/or lead/tin alloys small bubble characteristics and that of a fourinvolving forced convection, thermo/solutal natural sensor probe for the measurement of large slug

convection, and/or thermo/diffusocapillary bubbles or irregular large bubbles, it can be

convection. The calculations have revealed a applied to a wide range of flow regimes.

wide variety of rich and robust flow conditions, Furthermore by separately measuring the

including important physical features of the contributions from these two different groups of

solidification process which have been observed bubbles, the gradual changes in the interfacial

experimentally but have heretofore eluded structures associated with flow regime transition

prediction. These featuresincludedouble-diffusive can be quantified. Such an instrumentation

layering in the melt, development of an irregular method has never been developed previously.

liquidus front, remelting of solid, development of The double-sensor and multi-sensor probes are

flow channels in the mushy region, and the used for vertical two-phase flow to obtain detailed

establishment of characteristic macrosegregation data on the interfacial structure and its axial

patterns (regions of significantly different development from the entrance to the exit. The

composition) in the final solid. Theoretical and combination of these probes will give information

experimental studies have also revealed means by on the local void fraction, interfacial area, interface

which macrosegregation may be actively velocity, bubble size and turbulent characteristics

suppressed, as, for example, through the of the bubble motion in bubbly, slug and chumapplication of a magnetic field or intermittent turbulent flow. The changes in these parameters

rotation of the mold. quantitatively characterize the flow regime transitions from bubble to slug and slug to chumturbulent flow. Then this information will be used

Purdue University to understand the dynamics of fluid particle coalescence and disintegration as well as the

School of Nuclear Engineering $251,742 interfacial instability and their relation to the global West Lafayette, IN 47907 01-C changes in the interfacial structure or flow regime.

Intr 93- 3 Finally, the long term goal is to develop an

Interfacial Area and Interfacial Transfer iinterfacial area transport equation by Two-Phase Flow mechanistically modeling the contributions from

"~~~M. Ishii~ ~the particle coalescence, disintegration and

convection. The phase change, coalescence and

The objectives of the proposed research program disintegration effects appear as source and sink

are to develop instrumentation methods, terms in the transport equation. The major

experimental data base and analysis leading to mechanisms for the coalescence of fluid particles predictive models for describing the interfacial are particle collisions, wake entrainment and

structure and behaviors of two-phase flows. In bubble crowding into a form similar to a Taylor

terms of the flow structure, the transverse bubble, whereas the fluid particles disintegrate due

distributions of the local void fraction, interfacial

Engineering Research 41 1993
to turbulent effects. These different mechanisms techniques will extend the maximum heat flux to at

are modeled separately using a simple physical least 5x108W/m2, which would be higher than that

model and data obtained under Tasks 2 and 3. reported in any study to date. The wall

temperature characteristics and pressure drops

are unknown at such high heat fluxes. Particular

Purdue University emphasis is placed on the pressure drop, as the

School of Mechanical Engineering $119,733 CHF in many practical applications is determined

West Lafayette, IN 47907 01-B by the pressure drop characteristics.

93-3

Near-Wall Measurement of Sublayer An experimental program is systematically

Dryout and Theoretical Modeling of investigating the effects of subcooling, velocity,

CHF in Vertical Channels tube geometry, and enhancement techniques on

I. Mudawar CHF, the boiling curve, and the pressure drop. The CHF without enhancement has been

The proposed project will target the development correlated as a function of flow and geometrical

of a theoretical model for critical heat flux (CHF) in variables using the present data base of over 200

vertical upflow. Experiments will be performed points as well as data obtained by other

with the aid of a velocity/interfacial boundary investigators. The correlation describes well other

analyzer in order to examine near-wall conditions data recently published.

at heat fluxes approaching and exceeding CHF.

these measurements will determine the trigger A thesis (C.L. Vandervort, Ph.D.) and interim

mechanism for liquid sublayer dryout beneath the repor (HTL-9) descrbe the progress to date.

coalescent vapor layer which forms at high heat

fluxes. Instability feature (e.g. wavelength,

amplitude) of the wavy vapor-liquid interface will Rensselaer Polytechnic Institute

be measured over heaters of various lengths to Dept of Mechanical Engineering, $134,000

determine the frequency and spatial span of Aeronautical Eng & Mechanics 01-A

interfacial contact with the wall at heat fluxes Troy, NY 12180-3590 91-3

approaching CHF and explore the mechanism of

dryout in the contact regions. This information will Inelastic Deformation and Damage at High

be used to construct a validated theoretical model Temperature

applicable to vertical upflow in long channels and E. Krempl

to different fluids and channel configurations.

A combined theoretical and experimental

investigation is performed to study the biaxial

Rensselaer Polytechnic Institute deformation and failure behavior of engineering

Dept of Mechanical Eng, $ 0 alloys under low-cycle fatigue conditions at

Aeronautical Eng Mechanics 01-B elevated temperature. The purpose is to

Troy, NY 12180-3590 89-4 characterize the material behavior in mathematical

equations which are ultimately intended for use in

Ultimate Limits of Boiling Heat Fluxes inelastic stress analysis and life prediction.

A. Bergles, M. Jensen The modeling of effects of recovery of state

This study is directed toward the thermal-hydraulic observed in strain rate change and relaxation tests

behavior of water and aqueous mixtures, flowing at 538°C on modified 9Cr-1Mo Steel has been

in plain tubes and in tubes with enhancement completed. The Viscoplasticity Theory Based on

devices, at very high heat fluxes. The mode of Overstress (VBO) with a recovery of state term is

heat transfer is subcooled nucleate boiling, and capable of reproducing the observed behavior.

the limiting phenomenon is the critical heat flux Finite deformation formulations of VBO include a

(CHF). Very large heat fluxes can be modification of the growth law for the equilibrium

accommodated on a steady basis with pure water stress and a rationale for choosing objective

by use of large subcoolings, high velocities, small derivatives of stress-like state variables.

tube diameters, and short tubes. It is expected Numerical simulations are in progress.

that simultaneous use of several enhancement

Engineering Research 42 1993
Seven biaxial low-cycle fatigue tests with stainless Rensselaer Polytechnic Institute

steel tubular specimens at 538°C have been Dept of Chemical Engineering $88,379

completed. During these tests, the voltage drop Troy, NY 12180-3590 01-C

was monitored using a reversing DC potential drop 93-4

measuring apparatus. A new method of data Development and Use of Image Scanning

analysis and smoothing was developed which Ellipsometer to Study the Dynamics of Heat

showed a significant increase in voltage drop in Thin Liquid Films

the area of crack formation. Analysis of the P. Wayner, Jr.

theoretical solution for the voltage drop for a semielliptical crack in an infinite medium showed The physicochemical phenomena associated with

similar shapes. Testing and analysis are fluid flow and change-of-phase heat transfer in

continuing. ultra-thin (thickness less than 10-5 m) liquid films

are being studied. Microscopic image processing

equipment, procedures, and related computer

Rensselaer Polytechnic Institute programs are being developed to improve data

Dept of Nuc Eng & Eng Physics $ 0 resolution and automate data acquisition. First, the

Troy, NY 12180-3590 06-C image processing equipments are being developed

89-4 and used in conjunction with an interferometer

The Continuum Modeling of Two-Phase designed to study the transient film thickness in

Systems draining and evaporating films. The glass cell is

R. Lahey, Jr., D. Drew designed to optimize temperature control,

cleanliness and simplicity. The optical data is

This research is concerned with the development obtained using a video camera attached to a

of a physically-based, well-posed multidimensional microscope through which the interference fringes

two-fluid model which can be used for the are recorded. Transport processes in various

prediction of a wide variety of commercially fluids, with and without heat transfer, are being

important multiphase flows. experimentally studied and analyzed. Using the

results of these studies, an image processing

Significant progress has been made in the ellipsometer (which can measure thinnerfilms with

modeling of bubbly two-phase flows. The thicknesses down to a nanometer) has been

approach taken was to analytically derive the designed, constructed and used. The long term

various interfacial closure laws using cell-model, objectives are to measure and model transport

ensemble averaging techniques. In particular, it processes in thin films. The near term objective is

was assumed that the continuous (liquid) phase to develop microscopic image processing

was inviscid and irrotational. equipment and a complementary experimental cell.

The resultant two-fluid model has been numerically evaluated using PHOENICS, a computational fluid Rice University

dynamic (CFD) solver, and these results have Dept of Civil Engineering $87,560

been found to agree very well with a wide range of Houston, TX 77251 01-A

phase distribution data. Moreover, the dispersion 91-3

relation of this two-fluid model has shown that it is tochastic Quadrization for Probabilistic

capable of predicting both sonic and void wave Analysis of Large Compliant Off-Shore

propagation phenomenon and the bubbly/slug flow Structures

regime transition. P. Spanos

Further research is expected to focus on heat Nonlinear wave forces acting upon offshore

transfer phenomena, the effect of bubble distortion structures have been examined from a system

on lateral lift, the modeling of other flow regimes identification perspective. The nonlinearities are

and the modeling of two-phase turbulence induced by the wave-structure interaction effect, (particularly intermittency and the coherent d may become non-negligible in many and may become non-negligible in many structures). situations, especially for large energy producing

systems. They are not necessarily in Morison's

form in terms of squared relative velocities or they

Engineering Research 43 1993
are not calculated by diffraction theory. Various vortex line lattice. The loss of order in the parallel

wave force models have been examined. A direction has been associated with the onset of a

particular force function which is adopted for a vortex line tangle percolating throughout the entire

given class of problems has been expanded in system. New simulations, relaxing earlier

terms of the wave and structural kinematics. The approximations, are being carred out to clarify this

resulting nonlinear system has been decomposed issue. The effect of applied currents and random

into a number of parallel no-memory nonlinear vortex pinning sites will be added in future work.

systems, each followed by a finite-memory linear The dynamic behavior of vortices in two

system. For such multi-input linear sub-systems, dimensional Josephson arrays has also recently

a cross-spectrum technique involving Wiener- been investigated using a detailed finite size

Volterra kernels has been applied to identify the analysis to verify proposed scaling equations.

linear transfer functions, from which the structural

properties and the force transfer parameters have This research will greatly enhance the fundamental

been obtained by a least squares approximation. understanding of behavior in strongly fluctuating

The developed method provides a versatile and superconducting materials. The results will have

non-iterative approach for dealing with the impact in understanding the magnetic properties of

nonlinear interaction problems encountered in the new high temperature superconductors, and in

offshore structural engineering. Current studies the design of Josephson junction arrays for use as

aim to further establish the versatility and the microwave detectors and generators.

reliability of this method.

University Of Rochester

University Of Rochester Dept of Physics and Astronomy $93,500

Dept of Physics and Astronomy $69,500 Rochester, NY 14627 06-C

Rochester, NY 14627 06-C 93-3

92-3 Coherence Effects in Radiative Energy

Flux Flow, Pinning, and Resistive Behavior in Transfer

Superconducting Networks E. Wolf

S. Teitel

This research is mainly concerned with the

The fluctuation of vortices and vortex lines has elucidation of the foundations of radiometry and

been shown to be a major source of electrical radiative energy transfer and with the influence of

resistance for superconducting networks when source correlations on the energy distribution

placed in magnetic fields. Systems of particular throughout the radiated field.

interest include the new high temperature type II

superconductors, and periodic arrays of In the early stages of these investigations the

Josephson junctions. Numerical simulations are relationship of radiometry to statistical wave theory

being carried out to identify and characterize the for fields produced by a certain class of globally

nature of the various vortex structures present in incoherent sources was clarified. The present

such systems, as a function of temperature and research is concerned with extending this work to

applied magnetic field, and to understand the fields generated by sources of a broader class.

nature of the phase transitions between them. Frequency shifts in spontaneous emission from

two interacting atoms, was also investigated. This

Particular attention has recently been given to effect may be considered to be analogous, in

studying the equilibrium fluctuation of vortex lines some respects, to the Lamb shift.

in models of bulk high temperature

superconductors. The possibility of determining spatial correlation

functions of random media from the knowledge of

Simulations have shown that there can be two the correlation functions of the scattered field in

distinct phase transitions describing the the far zone is also being studied.

superconducting ordering parallel versus

perpendicular to the applied magnetic field. The

loss of order in the perpendicular direction has

been associated with a melting of the ground state

Engineering Research 44 1993
The Rockefeller University Sandia National Laboratories

Department of Physics $85,487 Combustion Research Facility $150,000

1230 York Avenue 06-C Thermofluids Division 06-B

New Yprk, NY 10021 92-3 Livermore, CA 94550 90-3

Some Basic Research Problems Related to Mixing and Phase Change During

Energy Combustion

E. Cohen A. Kerstein

The present project is concerned with the following This project involves analytical and computational

problems. 1. The investigation of new types of study of the effect of random advection on two

diffusion, discovered in Lorentz lattice gas cellular interrelated processes, molecular mixing and front

automata, is continued. In this gas point particles propagation. Some fundamental aspects of

move on a lattice occupied by deterministic advective effects are not well understood even for

scatterers. For randomly placed scatterers this simple flows involving a limited range of advection

gas can be considered as a dynamical system in length scales. These aspects include the species

a random environment. A beginning has been concentration distribution in statistically steady

made to investigate the case of periodically placed mixing configurations and, for propagation

scatterers. 2. A relation between the transport processes, the dependence of front surface area

coefficients (viscosity, diffusion) of a fluid in a on stirring intensity. In turbulent flow, involving a

nonequilibrium stationary state and its two wide range of length scales, a key problem is the

maximal Lyapunov exponents is further pursued. coupling between flow and mixing in cases for

This relation is based on the symmetry of the which mixing modifies flow energetics, as in

Lyapunov spectrum of the fluid. The class of buoyant stratified turbulence.

systems for which this symmetry holds is being

investigated. In addition, computer studies are The methodology employed in this project involves

made of the diffusion coefficient of particles in a analogies between physical processes subject to

periodic triangular Lorentz gas in equilibrium. random disturbances and stochastic processes. In

Since this transport coefficient can also be particular, a novel computational model of

expressed in terms of two Lyapunov exponents, turbulent mixing has been formulated in which

the connection between the two cases is being turbulent stirring is represented by non-linear

studied. 3. An analogy has been discovered mappings on a line, iterated according to a

between the structural relaxation of atomic liquids stochastic rule that incorporates turbulence scaling

and monodisperse concentrated colloidal laws. Comparisons to experimental results

suspensions, consisting of spherical particles. demonstrate substantial gains in predictive

This analogy can be understood via the kinetic capability relative to other methods.

theory of a hard sphere model of both fluid

systems. Applications to the visco-elastic and In future work, this and other models will be used

rheological behavior of concentrated colloidal to simulate and analyze the effect of random

suspensions are made providing a microscopic advection, especially turbulent advection, on

approach to these properties. mixing and propagation processes in combustion

and geophysical flows. Propagation processes of

interest include flame fronts in fuel-air mixtures

and acoustic fronts perturbed by ocean currents.

Engineering Research 45 1993
Sandia National Laboratories University Of Southern

Combustion Research Facility $ 0 California

Livermore, CA 94551-0969 06-B Dept of Mechanical Engineering $106,536

Los Angeles, CA 90089-1453 01-C Structure of Inverse Diffusion Flames in 91-3 91-3

Supercritical Fuel/Water Mixtures Particle Pressures in Fluidized Beds

R. Steeper C. Campbell

This project investigates the structure of diffusion The particle pressure represents the portion of the

flames in high-density fuel-water-oxidizer mixtures. momentum transport in a fluidized bed that can be

These hydrothermal flames are of practical attributed to the motion of particles and their

concern in the development of supercritical water interactions. Preliminary measurerents, in

oxidation as a waste destruction process. Yet the gas-fluidized beds, have shown that '.he particle

basic scientific understanding of such flames is pressures exerted on the side walls are primarily

limited. Sandia has built a laboratory-scale, due to the presence of bubbles and that the

hydrothermal flame reactor with optical access magnitude of the average particle pressure scale

suitable for imaging, laser velocimetry, and Raman with the bubble size. This work is continuing in a

spectroscopy diagnostics. Hydrothermal flames 2-D bed with the goal of trying to measure the

created in this facility exhibit characteristics distinct particle pressure field around bubbles. These

from atmospheric-pressure flames. One unique results are very surprising. It was anticipated on

characteristic of the high-density flames is a wide beginning this work that the particle pressure field

range of possible flame temperatures; another is around a bubble would be something like the

an insensitivity of flame height to fuel fraction. gas-pressure field in the sense that the particle The research program investigates this pressure changes induced by the bubble would be

unexpected behavior by performing experiments local to the bubble and would disappear far away.

with densities ranging from atmospheric to Instead, the results show that the largest supercritical. The program provides an opportunity pressures are observed in the wake behind the

to extend the basic scientific understanding of bubble. But, instead of being local, the pressures

diffusion flames by examining the effects of high increase as the bubble moves away and reach the

density and an aqueous environment. maximum when the bubble erupts from the bed.

This indicates that the bubble defluidizes the

In experiments conducted to date, the range of material in its wake; the particle pressures

conditions that leads to the ignition of increase in the far wake as more and more

methane-water-oxygen and methanol-water- defluidized material is piled on top of itself. There

oxygen flames has been measured. A future goal is some evidence that the material is refluidizing in

of the experiments is to map temperature, species, the far wake, but that is a very slow process. This

and velocity fields in the hydrothermal flame observation may have profound implications in

reactor. Both analytical and numerical models of chemical processing as their may not be sufficient

laminar diffusion flames are available to support intermingling of the gas and solid in the large

the experimental efforts. These models will be amount of defluidized material in the wake.

modified to include a supercritical fluid equation of

state, an appropriate reaction mechanism, and Work is also being performed in a liquid fluidized

high-pressure transport properties. bed to try and understand how particle pressures

are generated in the absence of bubbles. These

particle pressures are extremely small and

required a redesign of the particle pressure

transducer. The results show that the particle

pressures are a tradeoff between the particle

agitation and concentration. Thus, as the fluidizing

flow is increased, the particle pressures rise

immediately after minimum fluidization due to the

increased agitation, reach a maximum and then

drop off due to the reduced concentration.

Engineering Research 46 1993
University Of Southern Southwest Research Institute

California 6220 Culebra Road $99,979

Dept of Mechanical and $124,999 San Antonio, TX 78228-0510 03-B

Aerospace Engineering 01-C 91-3

Los Angeles, CA 90089 93-3 Application of Magnetomechanical Hysteresis

Modeling to Magnetic Techniques for

A Combined Experimental and Numerical Monitoring Neutron Embrittlement and Biaxial

Investigation of Multiphase Porous Media Stress

Flow Dynamics M. Sablik

T. Maxworthy, E. Meiburg The approach was to study the effects of neutron

This investigation of multiphase porous media embrittlement and biaxial stress on signals from

flows addresses two related issues: Part one of various magnetic measurement techniques in

the study deals with the question of the proper steels The purpose was to detemine which

interfacial boundary conditions to be applied in the procedures have promise for use in monitoring

interfacial region between two miscible fluids neutron embrittlement and biaxial stress.

moving in a Hele-Shaw cell or, by analogy, in a

porous medium. We hope to accurately determine For neutron embrittlement, six sets of broken

the characteristics of these interfaces by Charpy samples were examined from two reactors.

comparing experiments carried out in a Hele-Shaw In each set, the samples all corresponded to the

cell and a circular tube with numerical calculations same number of full power years, but each sample

of the full problem, based on the Stokes was positioned slightly differently in the

equations. By measuring the amount of viscous containment capsule and so received a different

fluid left behind during miscible displacement by a amount of irradiation. Each set nevertheless was

less viscous fluid, we hope to establish the spatial characterized by one value for each embrittlement

dependence of the gap-averaged concentration parameter, regardless of the differing amounts of

profile as a function of the Peclet number. By irradiation. Since a true measure of embrittlement

comparison with the numerical calculations as well was not available for each sample, the magnetic

as with immiscible displacement results, we will measurements exhibited a large statistical spread.

attempt to determine if the process can be The best correlation occurred for nonlinear

described in terms of an effective capillary harmonic amplitudes, with R2 of the order of 0.7

number, in which the concentration-gradient (rather than 1).

stresses at the interface zone might, possibly, give

rise to an effective surface tension. The Hele- On the other hand, guided by magnetomechanical

Shaw cell geometry will also be used to study the hysteresis modeling, a procedure has been

stability of miscible interfaces over a wide range of experimentally identified for measurement of the

conditions including the effect of a tangential difference o2-o, of two biaxial stresses.

velocity jump across the interface. In part two of Experiment and modeling exhibit agreement thus

the investigation, we will explore the nonlinear far in the case where hysteresis parameters are

dynamics of immiscible displacements under the used in stress monitoring. Other magnetic

influence of gravity on the basis of the recent techniques are now being tried for the stress

linear stability results. measurement.

The apparatus has been built to study miscible

displacement in circular tube as a function of both

Peclet and Atwood numbers. Results show a

strong dependence of the flow on the latter

parameter. A two-dimensional code has been

developed for studying the Peclet number

influence on miscible displacements. The code is

currently being tested.

Engineering Research 47 1993
Stanford University Stanford University

Dept of Mechanical Engineering $80,500 Division of Applied Mechanics $96,665

Stanford, CA 94305-3030 01-A Stanford, CA 94305-3030 01-A

93-3 91-3

Structure and Modelling of the Three- Stability and Stress Analyses of Surface

Dimensional Boundary Layers on a Rotating Morphology of Elastic and Piezoelectric

Disk Materials

J. Eaton H. Gao

The objectives of this research are to identify, The goal of this research is to investigate the

understand, and model the effects of mean flow mechanical effects of surface morphology of

three dimensionality on turbulent boundary layer elastic and piezoelectric materials. In particular,

heat transfer. The present experiments are the project will study the stability of material

examining the heat transfer and turbulence surfaces against diffusional perturbations and the

structure on a large disk rotating in a quiescent stress concentration caused by surface roughness.

environment. Single point measurements show

that the vertical mixing of momentum and heat is Besides work on piezoelectric surfaces, the most

suppressed bythe three dimensionality. Two-point important progress of this project has been the

velocity correlations in an air flow apparatus discovery that a cycloid-cusped microscopic rough

indicated that crossflow weakens the sweeps and surface is capable of generating crack-like stress

bursts which account for most of the production of singularities in the form of Dirac-singular strain

turbulent shear stress. During the past year, a energy pulses. A cusped cycloid surface induces

large water flow apparatus was developed a crack-like singular stress field and is the most

duplicating the airflow geometry. Laser Doppler efficient stress concentrator at a fixed wavelength.

anemometer measurements confirmed that the An important difference is also noted. Cracks are

flow accurately replicated the air flow. Flow active only under tensile stresses because of

visualization using high speed filming of hydrogen crack face contact under compression. In

bubbles confirmed our qualitative interpretation of contrast, cusps work both ways: they admit a

the two-point correlations showing conclusively positive value of mode I stress intensity factor

that the crossflow reduces the vertical motion under tension and a negative value under

during a significant fraction of bursting events. compression. Thin films in semiconductor devices

are often under compression due to lattice misfit,

Construction and qualification of a heat-transfer in which case the cusp provides a unique

disk for the airflow apparatus were completed and mechanism for stress concentration leading to

measurements were obtained for tip Reynolds mechanical failure.

numbers up to 850,000. A two-dimensional finite

element code was required to correct for back A computer algorithm is being developed to

losses due to the relatively large temperature simulate the evolution of a rough surface under

variation on the constant heat flux surface. This stress corrosion leading to the formation of stress

year, the emphasis will be on higher Reynolds singularities.

numbers and measurements of the turbulent heat

flux.

Engineering Research 48 1993
Stanford University numerically generalized eigenvectors of nonDept of Mechanical Engineering $175,000 semisimple matrices, which is a non-trivial

Stanford, CA 94305-3030 01-A computational problem. We are also examining 91-4 reflection and refraction of plane waves in

Energy Changes in Transforming Solids anisotropic bimaterials. During the coming year

G. Herrmann, D. Bamett we intend to return to an unresolved problem in

dislocation mechanics, namely the determination

In solid mechanics defects such as inclusions, of equilibrated dislocation distributions in elastic

holes, cracks, and dislocations may undergo solids under zero applied stresses; this critical

rearrangement as well as changes of size and problem must be solved if modem micromechanics

form. The energy changes associated with such is to prove capable of studying elastoplastic solids

rearrangements provide thermodynamic driving allowing for unloading.

forces which help characterize the response of

solids under loads to these "transformations", and

it is the determination and calculation of these Stanford University

driving forces which a portion of our research has Edward L. Ginzton Laboratory $285,000

as its aim. In the past year we have extended our Stanford, CA 94305-3030 03-B

methodology of heterogenization to treat certain 93-3

problems in 3-D elasticity, plane thermoelasticity, Optical Techniques for Superconductor

and antiplane piezoelectricity; the results obtained and Thin Film Characteriztion

are of significance in the areas of advanced G. Kino

composites and smart materials. In addition the

Neutral Action Method we have recently developed Photothermal measurements are used to study

has been applied to thermoelasticity, diffusion and fluctuation phenomena in high tempiezoelectricity, and porous media, and has perature superconductors. Phase delay

yielded much insight into analyses of defects and measurements yield the thermal diffusion, and

fracture in these systems. We have continued to measurement of the reflectivity of the probe beam

extend the thermodynamic theory of elastic solids yields a quantity closely related to the specific

prone to damage using a formalism based on the heat. Measurements have been made in

local state approximation. individual crystallites 20-50 micrometers across.

Below T., the peak value of the diffusion constant

Another portion of our work has as its objective within a grain is much higher than in other

the development of further understanding of measurements, and it is in good agreement with

subsonic and supersonic surface waves and of theory. Above Tc, a very large temperature drop

bulk and interfacial waves in anisotropic elastic is observed across grain boundaries in YBCO,

and piezoelectric media. Such waves can serve indicating phonon reflection at the grain boundary;

as useful probes in the non-destructive evaluation we also observe a diffusion constant within an

of matter, provided sufficient details about them individual crystallite of twice the normally

are well-understood. In the past year we have measured bulk value. Diffusion measurements

studied the existence of so-called "spaces of below T, in YBCO show good agreement with

simple reflection" (within which are to be found experiments on measurements of normal electron

supersonic surface wave solutions) in media with density as a function of temperature. The

no symmetry (triclinic symmetry). In particular, amplitude of the probing signal yields a quantity

we have found the extension of the space of closely related to the specific heat. In YBCO and

simple reflection in the neighborhood of a Bi2Sr2CaCu 2O8, measurements show a large peak

supersonic one-component Rayleigh wave in such at Tc and a rapid fall-off from the peak value, in

a solid (a space that had eluded earlier excellent agreement with the second order phase

investigations), and we are now studying where transition theory for fluctuations near the critical

and how such a space terminates with respect to point. Similar measurements of charge density

slowness surfaces. The latter is a delicate waves in NbSe2give good agreement with two-dicomputing problem that involves finding mensional phase transition theory.

Engineering Research 49 1993
Stanford University finite chemical reaction rates, nonequilibrium

Dept of Civil Engineering $ 0 electron densities and temperatures, and radiation

Stanford, CA 94305-4020 01-B loss effects. Advanced laser based methods are

90-3 being developed for measurement of plasma

Fluid Dynamics of Double Diffusive Systems parameters including species concentration and

J. Koseff, R. Street, S. Schladow temperature. The primary technique under study

is the application of degenerate four-wave mixing

A study of mixing processes in doubly diffusive (DFWM) to atmospheric pressure plasma

systems is being Conducted. Continuous environments in order to assess the importance of

gradients of two diffusing Components (heat and nonequilibrium effects under conditions of interest

salinity in our case) are being used as initial to plasma chemistry.

conditions, and forcing is introduced by lateral

heating and grid stirring. The goals of the Results with an induction plasma facility show

proposed work include: (1) quantification of the significant nonequilibrium within a downstream

effects of finite amplitude disturbances on stable, quartz test section, and suggest errors in

double diffusive systems. particularly with respect conventional diagnostics assuming local

to lateral heating, (2) understanding the role of thermodynamic equilibrium. Measurements of

Prandtl/Schmidt number on the mixing efficiency, radiation source strength in argon indicate an

evolution, and structure of turbulence in a stratified order-of-magnitude difference from values reported

fluid, and (3) increasing our knowledge-base on earlier at temperatures of interest in plasma

turbulent flow in stratified environments and how to processing.

represent it. The work is being carried out in an

experimental facility which is located in the To investigate the application of advanced laser

Stanford Environmental Fluid Mechanics diagnostics to a realistic and promising form of

Laboratory. Our current research ideas are plasma processing, experiments have been

centered around the fact that while fluids are undertakenonthereactingplasmaboundarylayer

stirred by turbulence they are not mixed until of a substrate placed in a diamond producing

molecular diffusion occurs. By stretching and plasma flow Growth rate of diamond films in

folding surfaces of constant concentration and these environments has been demonstrated to be

reducing the distance between them the over an order of magnitude greater than those

turbulence sharpens the gradients and increases characteristic of low-pressure diamond synthesis

the diffusive flux. Thus turbulence enhances systems.

mixing but only molecular diffusion can perform

the actual mixing. The research we are planning Recent experiments using DFWM to probe CH

includes defining a parameter that measures and C2 within the reacting plasma have

efficiency of mixing and not just stirring, demonstrated the ability to provide sensitive (ppm

developing linear theory and extending a time level) detection with submillimeter spatial

scale analysis to predict the effects of molecular resolution in the measurement of vibrational

diffusion on mixing efficiency, and measuring the temperatures, rotational temperatures, and species

efficiency over a range of stratifications in a concentrations.

system stratified by salt, heat, and/or both.

Stanford University

Stanford University Dept of Chemistry $194,828

Mechanical Engineering Dept $441,508 Stanford, CA 94305 06-C

Stanford, CA 94305 03-B 92-3

92-4 Thermodynamics and Stochastic Theory of

Advanced Diagnostics for Plasma Chemistry Hydrodynamics and Power Producing

C. Kruger, T. Owano Processes

J. Ross

This research is concerned with optical diagnostics

for plasma chemistry and plasma processing, with Research focuses on the thermodynamic and

an emphasis on methods that allow for departures stochastic theory of hydrodynamic processes, such

from local thermodynamic equilibrium -- such as as combinations of chemical reactions, diffusion,

Engineering Research 50 1993
thermal conduction, and viscus flow, Such interface. The CH temperature is found to fall

theories have been formulated for each of the monotonically from nearly 4000 K in the freeindividual processes, both Linear and nonlinear. stream to 1200 K at the surface. Simultaneously

Progress has been made on combinations of the mole fraction of CH and C2 rises and falls, with

these processes for a simplified form of the a maximum 200 microns above the surface.

Navier-Stokes equations, the so-called Lorenz Excellent agreement is found between measured

equations. The theory leads to a formulation of an profiles and those predicted with a one-dimension

excess work expressed in terms of thermodynamic computational model.

functions, which provides a Uapunov function,

necessary and sufficient conditions of stability,

criteria of relative stability, and relations to Stevens Institute Of Technology

fluctuations. Concurrent Research is done on ept Engineering $7,000

systems with multiple stationary states and limit Hoboken NJ 07030 06-C

cycles. Work is planned on the formulation of 92-3

thermodynamics of nonlinear (autocatalytic) Investigation of Transitions From Order to

chemical reactions which produce work or on Chaos in Dynamical Systems

which external work is done; and a similar G. Schmidt, A. Chernikov

formulation for systems with more than one

temperature. Basic properties and applications of chaotic

dynamical systems are studied, analytically as well

as computationally. Stanford University

Dept of Chemistry $95,328 1. A fast dynamo is a highly conductive fluid in

Stanford, CA 94305 03-A stationary chaotic motion that enhances a small

92-4 seed magnetic field exponentially. It has been

Degenerate Four-Wave Mixing as a conjectured that solar and stellar magnetic fields

Diagnostic of Plasma Chemistry are generated by such a process. Recently we

R. Zare have identified the first realistic candidate for fast

dynamo action. A convective cell ( fluid heated

This research project concens the development of from below ) has been studied analytically and

degenerate four-wave mixing (DFWM) for in situ computationally, and exponential growth of a seed

diagnostics of the boundary-layer region in magnetic field over several orders of magnitude

atmospheric-pressure reactive plasmas. The has been detected on the computer model. A new

emphasis is on nonintrusive and state-specific numerical scheme, the fractal grid method, has

techniques for monitoring the concentration, been developed to measure the magnetic flux

temperature and spatial distribution of transient reliably. In this model the fluid had infinite

radical species during plasma processing. DFWM conductivity. To measure the effect of finite (but

is a highly sensitive laser-based nonlinear very large) conductivity a new numerical method

spectroscopy yielding a coherent signal beam that has been developed, and future work will

can be detected remotely, free from the concentrate on the computation of this model with

interferences of background luminescence. finite conductivity. One expect a slower flux growth

with this more realistic model, and the aim is to

Recent experiments using DFWM to probe CH find the growth rate as a function of conductivity.

and C2 during the plasma synthesis of diamond

thin films have demonstrated the ability to provide 2. Charged particle beams are often afflicted by a

parts-per-million-level detection with submillimeter process called emittance growth, reducing beam

spatial resolution in the measurement of rotational quality. We intend to study this process on the

temperatures, vibrational temperatures, and basis of chaotic motion of beam particles.

species concentration. These experiments are Cylindrical beams will be studied, moving in a

conducted in an industrial-scale 50 kW inductive confining field as well as the self consistent field

plasma reactor operating with argon, hydrogen produced by the charged particles. Preliminary

and methane. The critical region is a narrow (less studies indicate emittance growth due to chaotic

than 1 cm thick) boundary layer at the gas-surface effects once cylindrical sheets cross.

Engineering Research 51 1993
Texas A&M University dynamics. For unstable dynamical systems, there

Petroleum Engineering $143,257 are different classes; this includes dynamical

College Station, TX 77843 06-C maps. Recent work by this group shows that the

93-2 evolution operator of the probability distribution

Hydrocarbon/CO2 /Water Multiphase admits an irreducible spectral representation with

Equilibrium Separations complex eigenvalues related to the Lyapounov

C. Wu exponents. This representation is in generalized

spaces (so-called "rigged" Hilbert spaces). The

The objectives of this research project are: (1) eigenfunctions are distributions (which are, in

conducting experimental measurements of phase general, fractals) that have to be used in

equilibria for mixtures of selected hydrocarbons conjunction with test functions. This excludes the

with CO, and water at pressures up to 10,000 psia consideration of individual trajectories and implies

and at temperatures up to 500°F and (2) therefore an irreducible statistical description. The

developing a rigorous computer simulator (EOSS) existence of such irreducible representation can be

using the Wong-Sandler mixture combining rules considered as the very definition of chaos.

and "Area Method" for laboratory data analysis

and general applications. for laboraThese representations also can be constructed for

an important class of classical and quantum

Two existing laboratory apparatus will be modified systems, called "Large Poincare Systems" (LPS),

for the experimental work. A high-pressure characterized by a continuous set of resonances.

mercury-free window cell will be upgraded to Most systems in nature are LPS. As a simple

conduct the laboratory experiments to 400°F. A example, potential scatterings have been studied

high-temperature distillation cell will be modified in detail. It has been shown that the usual

for experimental tests to 5000F. The experiments spectral representations of the Hamiltonian or of

will use n-alkanes having carbon numbers from C, the Liouville operator fail for persistent scattering;

to C,2, naphthenes and aromatics, C02 and crude moreover, these are the first examples that show

oils. Sufficient basic laboratory data will be the limit of trajectory dynamics in classical systems

collected and analyzed to determine three-phase and also the limit of quantum mechanics based on

K-Va!ues and phase properties using empirical wave functions. The results have been verified by

correlations and the rigorous equation of state numerical simulations For the persistent scatterapproach. ing, new spectral representation that is irreducible

has been constructed in generalized spaces (it

Existing phase-behavior computer simulators will cannot be expressed in terms of wave functions).

be upgraded concurrently with the experimental This representation incorporates into dynamics

work to describe the multiphase equilibrium dissipativity, as well as approach to equilibrium.

separations. multiphase computer simulators will

be verified with the experimental data for practical Several applications of the new spectral

applications in compositional reservoir engineering representation are in progress. These are matterand enhanced oil recovery, and for process design field coupled systems (quantum optics, field-field

and chemical separation in chemical industry. coupled systems, evaluation of genuinethree-body scattering cross section, causal behavior of the

Lorentz gas, and so on.

University Of Texas At Austin

Ctr for Studies in Statistical Mech $100,003 University Of Texas At Austin

and Complex Systems 06-C University Of Texas At Austin and Complex Systems 06-C

Austin, TX 78712 91-3 Dept of Physics $182,883 Austin, TX 78712 06-C

The Behavior of Matter Under Non- 9 3

Equilibrium Conditions: Fundamental Complex Spatiotemporal Patterns in

Aspects and Applications Nonequilibrium Systems

I. Prigogine, T. Petrosky H. Swinney

A significant development has been achieved in The formation and evolution of spatiotemporal

the fundamental aspects of non-equilibrium patterns is being studied in chemical and physical

Engineering Research 52 1993
systems maintained far from equilibrium. The goal (b) The mechanics of crack-microcrack

is to understand what features are common in interactions in an anisotropic environment. A

diverse pattern-forming systems ranging from fluid variety of representative geometries was examined

flows to chemical systems. When does a spatial and the impact of different elastic constants of the

pattern spontaneously emerge in an initially matrix was analysed.

homogenous system as the external stress is

varied, and what kinds of bifurcations between (c) The effective elastic properties of anisotropic

different patterns are allowed? How can concepts matrices with arbitrarily oriented and interacting

from dynamical systems theory elucidate the cracks.

dynamics of nonequilibrium systems?

Experiments and analyses are addressing these 2. Work on the effective elastic properties of

questions for convecting fluids, electrodeposition, materials with holes of arbitrary shapes was

and chemical systems. Experiments on started. Preliminary results have been obtained

reaction-diffusion systems have revealed a variety for holes of elliptical shapes.

of spatiotemporal patterns that arise solely from

competition between chemical kinetics and mass

diffusion (convection is prevented by using novel United Technologies Res Center

gel-filled reactors). A traveling front type pattern Process Diagnostics Lab $ 0

has been found that differs from previously studied Silver Lane 03-A

chemical patterns, but the experiments and East Hartford, CT 06108 92-1

simulations indicate that such patterns could often

arise in spatially extended nonequilibrium systems. Investigation of PACVD Protective Coating

The comparison of experiment and theory for Processes Using Advanced Diagnostic

different types of systems should provide general Techniques

insights into the formation of spatial and temporal W Roman, S. Hay, F. Otter, A. Eckbreth

patterns in nonequilibrium systems.

The research objective is the comprehensive

experimental investigation of the fundamental Tufts University nonequilibrium reactive plasma assisted chemical

Dept of Mechanical Engineering $59,798 vapor deposition (PACVD) process as applied to

Medford, MA 02155 01-A hard face coatings (e.g. TiB2 or diamond).

92-3 Nonintrusive laser diagnostics (e.g. laser induced

Effective Elastic Properties and

Constitutive Equations for Brittle fluorescence (LIF) and coherent anti-Stokes

Solids Under Compression Raman spectroscopy (CARS)) are being used to

M. Kachanov probe gas phase species, concentrations and

rotational temperatures in situ. Detailed coating

Work done under the contract concentrated on the characterization is accomplished using Auger, Ion

following problems. Scattering and secondary ion mass spectroscopies

(AES, ISS and SIMS) and complementary

1. Investigations of the mechanics of defects in an techniques. In addition, coating characteristics

anisotropic environment. This investigation, rather such as smoothness, adhesion (UTRC custom

broad in scope, includes the following topics: built pin-on-disc apparatus) and hardness (stateof-the-art nanoindenter apparatus) are measured.

(a) The impact of matrix anisotropy on the Gas phase spectroscopy is interpreted through

mechanics of crack interactions. It was found, in chemical kinetic modelling and will be correlated to

particular, that the matrix anisotropy enhances the coating characteristics thus providing a predictive

interactions if loading is applied along the stiffer capability that is severely lacking in the present

direction of the matrix, and that it weakens the science base of advanced protective coatings.

interactions if loading is applied along the softer These techniques are also applicable to other

direction of the matrix. This effect is strongly processes such as PVD, CVD, combustion and

asymmetric: the enhancement effect is much thermal plasma deposition. Results to date

more pronounced than the weakening effect. include:

Engineering Research 53 1993
1) fabrication of a 5 kW rf PACVD reactor the aid of CCD cameras. Such a class of

system systems, called "Visually guided Control Systems,"

2) exploratory spectral emission studies have the capability to use visual information to

3) development of substrate preparation provide sutomatic feedback control to a

technology and characterization dynamically moving system. An example of such

4) implementation of a ultramicrohardness a system is a robotic manipulator with a set of

tester and adhesion test apparatus and cameras attached operating in an unstructured

analysis of coating hardness and elastic environment.

modulus

5) coating durability testing using UTRC We propose a new dynamical systems approach

erosion test facility to vision and to vision based control system

6) initial characterization of TiB2 and diamond design problems that is new both to the area of

coatings Computer Vision and to the area of Control

7) first time CARS observation of diborane System Design. The propsed project, based on a

(B2H6) in a PACVD process new theory of "Prospective Systems," promises to

8) in situ axial concentration and temperature enrich the field of Computer Vision especially in

profiles of key species (diborane and H2) in the area of Motion and Shape estimation of

2 - 5 torr pressure range in a diborane/Ar dynaically moving objects in an environment. It

plasma also introduces new challenges in System Theory,

9) formulation of chemical kinetic models for wherein feedback control is generated by visual

diborane pyrolysis sensors based onthe theory of nonlinear regulation

10) comparison with experimental results and nonlinear optimal control. The proposed

indicate thermal pyrolysis is not the project undoubtedly broadens the technology and

mechanism for chemical initiation conceptual base while introducing some new

11) proposal of surface species and promising appraoches to visually guided control

heterogeneous reaction mechanism for the systems.

growth of boron from diborane plasma

12) extension of in situ laser diagnostics to

diborane/Ar plasma in the 1-10 torr pressure Washington State University

range Dept of Mech & Matls Engineering $ 0

13) in situ axial concentration and temperature Pullman, WA 99164-2920 01-B

profiles of diborane in the 1-10 torr pressure 91-2

range in a diborane/TiCI4/Ar plasma Mass and Energy Coupling Effects in

14) observation of emission spectra of diborane/ Multiphase Free Shear Flows

Ar and diborane/He plasmas indicate T. Trourf

chemistry is initiated by electron impact

dissociation of diborane and is not The primary goal of this research program is to

photoinitiated examine the effects of two-way multiphase 15) surface chemical kinetics incorporated into coupling on the development of organized vortex

analytical model structures in free shear flows and the resultant

multiphase dispersion. Previous research studies

have determined that one-way coupled particle

Washington University dispersion in free shear flows is strongly

Department of Systems Science $75,999 dependent on the vortex structures present in

and Mathematics 03-A these flows and their interactions as well as the

Saint Louis, MO 63130 93-3 ratio of the particle aerodynamic response time to

the time scale of the dominant vortex structures.

Visually Guided Control Systems: A New

Generation of System Analysis and Design Current research efforts are directed towards

B. Ghosh exploring the effects that two-way momentum,

mass and energy coupling have on the multiphase

The main objective of the proposed project is to free shear flow dispersion processes previously

study dynamical systems that are controlled with uncovered. These efforts involve analytical,

Engineering Research 54 1993
numerical and experimental investigations. Recent mechanistic models for coalescence and

results indicate that momentum coupling effects disintegration of fluid particles. This transport

can change the linear stability characteristics of equation describes dynamical change of the

multiphase mixing layers and wakes. In addition interfacial structure and replaces the conventional

numerical results demonstrate that the large scale model based on flow regime transition criteria.

vortex structure development can be significantly

altered in two-phase mixing layers and wakes The proposed research program will provide: a) a

through two-way mass and momentum coupling new scientific instrumentation method for studying

interactions. These multiphase coupling effects detailed interfacial characteristics of two-phase

may have significant importance with regard to flow, b) benchmark data for the local interfacial

predicting and controlling the performance of area concentration, void fraction distribution,

energy conversion systems. interfacial wave structure, relative velocity and

wave propagation velocity for horizontal two-phase

flow systems, c) mechanistic models for fluid

University Of Wisconsin particle coalescence and disintegration, and d)

Mechanical Engineering Dept $231,878 interfacial area transport equation.

Milwaukee, Wl 53201 01-C

93-3

Interfacial Area and Interfacial Transfer in University Of Wisconsin

Two-Phase Flow Systems Dept of Chemical Engineering $114,000

G. Kojasoy Madison, Wl 53706 03-A

92-3

The objectives of the proposed research program New Process Modeling, Design, and Control

are to develop instrumentation methods, an Strategies for Energy Efficiency, High

experimental data base, and an analysis leading to Product Quality, and Improved Productivity in

predictive models for describing the interfacial the Process Industries

structure and behaviors of horizontal two-phase W. Ray

flows. In terms of the flow structure, the

transverse distributions of the local void fraction, The process industries are having great difficulty

interfacial area concentration, fluid particle size competing in the world market because of high

and their axial development from the entrance to energy costs, high labor rates, and old technology

the exit will be the primary focal point of the for many processes. This project is concerned

research. For the purpose of understanding the with the development of process design and

dynamic behaviors, the interfacial velocity, wave control strategies for improving energy efficiency,

characteristics, fluid particle coalescence and product quality, and productivity in the process

disintegration will be studied. The axial changes industry. In particular, (1) the resilient design and

in the distribution of void fraction and interfacial control of chemical reactors, and (2) the operation

area give the information on the particle of complex processing systems, will be

coalescence and disintegration. These will be investigated. Major emphasis in part (1) will be on

characterized by the collision frequency and two important classes of chemical reactors:

interfacial energy and turbulence in the liquid. polymerization processes and packed bed

reactors. In part (2), the main focus will be on

A special emphasis will be placed on the further developing process identification and control

improvement of the multi-sensor resistivity probe procedures which allow the design of advanced

method which has been successfully developed control systems based on limited process

and cross-calibrated against other global information and which will work reliably when

techniques. The multi-sensor probes will be used process parameters change in an unknown

together with hot-film probes for the liquid manner. Specific topics to be studied include new

turbulence measurements. These new process identification procedures, nonlinear

measurements will give sufficient information to controller designs, adaptive control methods, and

evaluate the local relative velocity and momentum techniques for distributed parameter systems.

interaction between phases. Final focus of the Both fundamental and immediately applicable

modeling effort is to develop interfacial area results are expected. The theoretical

transport equation which incorporates the developments are being tested experimentally on

Engineering Research 55 1993
pilot scale equipment in the laboratory. These

experiments not only allow improvements in

theoretical work, but also represent real life

demonstrations of the effectiveness of the

methods and of the feasibility of implementing

them in an industrial environment. The new

techniques developed in this project will be

incorporated into computer-aided design packages

and disseminated to industry. Therefore, it is

expected that the work will have an impact on

industrial practice.

Engineering Research 56 1993
Budget Number Index

Mechanical Sciences:

01-A Solid Mechanics: macroscopic aspects of elastic and plastic deformations,

and crack propagation

01-B Heat Transfer

01-C Fluid Mechanics

01-D Tribology

Control Systems and Instrumentation:

03-A Control systems, large scale systems

03-B Instrumentation for hostile environment, and NDE

03-C Intelligent systems

Engineering Data and Analysis:

06-A Thermophysical properties and processes

06-B Combustion

06-C Non-linear dynamics and engineering analysis
Budget Page

Number Number

01-A

Chaos in Fluid-Structure Systems .................................... 1

Bounds on Dynamic Plastic Deformation ...... ......... . .............. 2

Continuum Damage Mechanics - Critical States ......................... 3

An Investigation of History Dependent Damage in Time Dependent

Fracture Mechanics ....................................... ...... 3

A Micromechanical Viscoplastic Stress-Strain Model with Grain Boundary Sliding . . 13

Chaos in Fluid-Structure Systems ................... ................. 14

Elastic-Plastic Fracture Analysis Emphasis on Surface Flaws ................. 18

Stress Induced Phase Transformations ................................. 20

Modeling and Analysis of Surface Cracks .............................. 27

Basic Engineering Sciences of Solids Comminution ........................ 28

Inelastic Deformation and Damage at High Temperature .................... 42

Stochastic Quadrization for Probabilistic Analysis of Large Compliant

Off-Shore Structures ............................................ 43

Structure and Modellin gof the Three-Dimensional Boundary Layers

on a Rotating Disk .................... ......................... 48

Stability and Stress Analyses of Surface Morphology of Elastic and

Piezoelectric Materials ................... ........................ 48

Energy Changes in Transforming Solids ................................ 49

Effective Elastic Properties and Constitutive Equations for Brittle

Solids Under Compression .................... .................... 53

01-B

Film Cooling in a Pulsating Stream ................... ................ 2

Thermal Radiation and Conduction in Microscale Structures .................. 4

Heat Transfer to Viscoelastic Fluids ................................... 20

Stability and Rupture of Thin Fluid Films on Heated Solid Surfaces ............ 34

Radiative Transfer Through an Array of Discrete Surfaces ................... 37

Radiative Transfer Through Arrays of Discrete Surfaces with Fixed Orientation .... 38

Near-Wall Measurement of Sublayer Dryout and Theoretical Modeling of

CHF in Vertical Channels ....................................... 42

Ultimate Limits of Boiling Heat Fluxes ................................ 42

Fluid Dynamics of Double Diffusive Systems ............................ 50

Mass and Energy Coupling Effects in Multiphase Free Shear Flows ............ 54
01-C

Hydrodynamic Instabilities and Coherent Structures ........................ 1

Basic Studies of Transport Processes in Porous Media ...................... 5

Turbulence Structure and Transport Processes in Wavy Liquid Streams .......... 9

Lift and Drag Forces on Droplets and Particles in Wall-Bounded Flows .......... 13

Experiments in Turbulent Mixing .................................... 15

Two-Phase Potential Flow ......................................... 16

Experimental and Analytical Investigations of Flows in Porous Media ........... 16

Gas-Liquid Flow in Pipelines ....................................... 20

Numerical and Physical Modelling of Two-Phase Flow Phenomena at Large

Reynolds Numbers .................................... ......... 21

Turbulence Theory ........... ................................... 21

Lagrangian Analysis of Contaminant Dispersal in Bounded Turbulent Shear Flows . 24

Stability and Heat Transfer in Time-Modulated Flows ...................... 25

Rheological and Flow Characteristics of Dense Multiphase Slurries Employing a

Bim odal M odel ............................................... 28

Lubricated Transport of Viscous Materials ................. ............. 29

Effects of Capillarity of Macroscopic Flow in Porous Media . ...... .......... 34

Wave Dynamics on Falling Films and Its Effects on Heat/Mass Transfer ......... 35

Study of Interfacial Behavior in Cocurrent Gas-Liquid Flows . ...... .......... 36

Active Control of Convection ....................................... 38

Effect of Forced and Natural Convection on Solidification of Binary Mixtures ..... 41

Interfacial Area and Interfacial Transfer in Two-Phase Flow ................. 41

Development and Use of Image Scanning Ellipsometer to Study the Dynamics

of Heat Thin Liquid Films ........................................ 43

Particle Pressures in Fluidized Beds ................................... 46

A Combined Experimental and Numerical Investigation of Multiphase

Porous Media Flow Dynamics .................. ................... 47

Interfacial Area and Interfacial Transfer in Two-Phase Flow Systems ........... 55

01-D

Characterization of Metal Cutting Dynamics ............................. 22

Cryotribology (Low Temperature Friction and Wear) Development of

Cryotribological Theories and Application to Cryogenic Devices ............. 27

03-A

Modeling for Process Control .... ........... ....................... 10

Integration of Redesign Methodologies for Chemical Processes ................ 10

Application of Intelligent Control Systems to Mixed-Culture Bioprocesses ........ 17

Intelligent Control of Thermal Processes ............................... 19

Model Building, Control and Optimization of Large Scale Systems ....... ...... 19

A General Procedure for the Synthesis of Process Flowsheets . ......... ........... 25

Synthesis and Optimization of Integrated Chemical Processes ................. 26

Partial Control of Complex Processing Systems ....................... ... 32

Degenerate Four-Wave Mixing as a Diagnostic of Plasma Chemistry .... ........ 51
03-A

Investigation Of PACVD Protective Coating Processes Using Advanced

Diagnostic Techniques ........................................... 53

Visually Guided Control Systems: A New Generation of

System Analysis and Design ....................................... 54

New Process Modeling, Design and Control Strategies for Energy Efficiency,

High Product Quality, and Improved Productivity in the Process Industries ...... 55

03-B

Nondestructive Evaluation of Superconductors ........................... 19

Two-Phase Flow Measurements by NMR ............................... 22

Pulse Propagation in Inhomogeneous Optical Waveguides ................... 23

Metal Transfer in Gas Metal Arc Welding .............................. 26

Multivariable Control Of The Gas-Metal Arc Welding Process ................ 26

Development of Measurement Capabilities for the Thermophysical

Properties of Energy-Related Fluids .................................. 31

Thin-Film Characterization and Flow Detection ........................... 33

Application of Magnetomechanical Hysteresis Modeling to Magnetic

Techniques for Monitoring Neutron Embrittlement and Biaxial Stress .......... 47

Optical Techniques for Superconductor and Thin Film Characterization .......... 49

Advanced Diagnostics For Plasma Chemistry ............................ 50

03-C

Research on a Reconfigurable and Reliable Manipulators .................... 11

The Mechanics of Redundantly Driven Robotic Systems .................... 24

Center for Engineering Systems Advanced Research (CESAR) ................ 36

06-A

Three Phase System Modelling ...................................... 16

In-Flight Measurement of the Temperature of Small, High Velocity Particles ...... 17

Modeling of Thermal Plasma Processes ............................. ... 18

Experimental and Theoretical Studies of Multicomponent Vapor Condensation ..... 39

Transport Properties Of Disordered Porous Media From The Microstructure ....... 40

06-B

Fundamental Studies of Spray Combustion .............................. 6

Experiments on the Gas Dynamics of the HVOF Thermal Spray Process ......... 39

Mechanisms and Enhancements of Flame Stabilization ...................... 40

Mixing and Phase Change During Combustion ........................... 45

Structure of Inverse Diffusion Flames in Supercritical Fuel/Water Mixtures ....... 46
06-C

Dynamics of Electronegative Plasmas for Materials Processing ................ 4

Linear Kinetic Theory and Particle Transport in Stochastic Mixtures ............ 5

Nonlinear Waves in Continuous Media ............................... ....... 6

Nonperiodic, Broadband Signals: Signal Processing in Chaos .......... ....... 6

Noisy Nonlinear Systems ...................... .................... 7

Knot Invariants and the Thermodynamics of Lattice Gas Automata ............. 7

Structure of Turbulence, Conditional Averaging and Subgrid-Scale Modeling ...... 8

Traveling-Wave Convection in Fluid Mixtures ... .......... .............. 8

Bifurcations and Patterns in Nonlinear Dissipative Systems ............ ...... 9

Finite-Time Thermodynamics and Effective Energy Use ................... 12

Fundamentals and Techniques of Nonimaging Optics ................... .... 12

Mixing and Settling in Continuous Metal Production ....................... 15

Studies in Nonlinear Dynamics .................. .................. 22

Mathematical Models of Hysteresis .... ... ...................................... 23

Macrostatistical Hydrodynamics ....... ...... ...................... 29

Thermal Plasma Processing of Materials ............................... 30

Department of Energy Integrated Manufacturing Fellowship Program ........... 30

Industrial Liaison Pilot Program ................. ............ ....... 31

Low Resistivity Ohmic Contacts Between Semiconductors and High-Tc

Superconductors ............................................... 32

The Rheology of Concentrated Suspensions .............. .............. 32

Studies in Premixed Combustion ...... ............................ 33

Mixing of Immiscible Fluids in Chaotic Flows and Related Issues ............. 34

Stability and Dynamics of Spatio-Temporal Structures ...................... 35

Turbulence and Spatio-Temporal Chaos ....... ............................ 36

The Evolution of a Hele-Shaw Interface and Related Problems in Dendritic

Crystal Growth ..... ..... ..................................... 37

The Continuum Modeling of Two-Phase Systems ......................... 43

Flux Flow, Pinning, and Resistive Behavior in Superconducting Networks ........ 44

Coherence Effects in Radiative Energy Transfer ......................... 44

Some Basic Research Problems Related to Energy ........................ 45

Thermodynamics and Stochastic Theory of Hydrodynamics and Power Producing

Processes ............................................ ........ 50

Investigation of Transitions From Order to Chaos in Dynamical Systems ......... 51

Hydrocarbon/CO2 /Water Multiphase Equilibrium Separations ................. 52

The Behavior of Matter Under Nonequilibrium Conditions: Fundamental Aspects

and Applications .............................................. 52

Complex Spatiotemporal Patterns in Nonequilibrium Systems ................. 52
Principal Investigators

H. Abarbanel 6 B. Ghosh 54 K. Lindenberg 7 S. Schladow 50

J. Achenbach 33 A. Graham 29 R. Littlejohn 22 G. Schmidt 51

A. Acrivos 32 L. Gratton 5 M. Malone 25 H. Sehitoglu 20

G. Ahlers 9 I. Grossmann 10 R. Mann 36 J. Sengers 31

S. Altobelli 22 T. Hanratty 20 T. Maxworthy 47 G. Settles 39

G. Andrews 16,17 D. Hardt 26 I. Mayergoyz 23 J. Sheridan 31

J. Balint 24 J. Hartnett 20 F. McClintock 27,28 R. Shinnar 32

S. Banerjee 9 S. Hay 53 M. McCready 36 G. Sivashinsky 33

S. Bankoff 34 W. Haynes 31 J. McLaughlin 13 H. Smartt 19

D. Barnett 49 F. Hayot 36 E. Meiburg 47 P. Spanos 43

P. Barton 26 J. Heberlein 30 C. Menyuk 23 R. Steeper 46

T. Basar 19 G. Herrmann 49 D. Meyer 7 D. Stoner 17

H. Bau 38 G. Hetsroni 9 M. Miksis 34 R. Street 50

R. Behringer 16 F. Incropera 41 I. Minis 22 C. Surko 8

B. Berger 22 M. Ishii 41 M. Moldover 31 H. Swinney 52

A. Bergles 42 Y. Iwasa 27 L. Mondy 29 S. Tanveer 37

P. Bernard 24 C. Jayaprakash 36 F. Moon 14 S. Teitel 44

S. Berry 12 M. Jensen 42 M. Morari 10 K. Telschow 19

L. Biegler 10 J. Johnson 17,19 J. Moreland 32 C. Thompson 25

H. Brenner 29 E. Jordan 13 1. Mudawar 42 G. Thompson 10

F. Brust, Jr. 3 D. Joseph 29 E. Novikov 8 C.-L. Tien 4

C. Campbell 46 M. Kachanov 53 F. Otter 53 S. Torquato 40

D. Cannell 9 T. Kanade 11 J. Ottino 34 V. Travkin 5

A. Caprihan 22 A. Kaufman 22 T. Owano 50 T. Troutt 54

I. Catton 5 R. Kayser 31 D. Parks 27 L. Tsai 24

C. Chang 18 A. Kerstein 45 C. Peterson 28 K. Walker 13

H.-C. Chang 35 P. Khosla 11 T. Petrosky 52 J. Wallace 24

S. Chen 1 G. Kino 49 E. Pfender 30 G. Wallis 16

A. Chernikov 51 G. Kojasoy 55 F. Pin 36 Z. Warhaft 15

E. Cohen 45 P. Kokotovic 19 G. Pomraning 5 P. Wayner, Jr. 43

S. Davis 34 J. Koseff 50 I. Prigogine 52 J. Welty 37

J. Douglas 25 R. Kraichnan 21 R. Probstein 28 A. Westerberg 10

D. Drew 43 D. Krajcinovic 3 A. Prosperetti 21 G. Wilemski 39

M. Drost 38 E. Krempl 42 S. Putterman 6 F. Williams 6

T. Eagar 26 C. Kruger 50 J. Ramshaw 18 R. Winston 12

J. Eaton 48 B. Kuhn 30 W. Ray 55 E. Wolf 44

A. Eckbreth 53 H. Kytomaa 28 W. Reuter 18 C. Wu 52

J. Ekin 32 R. Lahey, Jr. 43 H. Richter 15 I. Wygnanski 2

L. Evans 26 J. Lang 26 H. Riecke 35 B. Wyslouzil 39

J. Fincke 17 C. Law 40 I. Rinard 32 C. Youngdahl 2

A. Frenkel 1 P. Libby 6 W. Roman 53 R. Zare 51

E. Fukushima 22 A. Lichtenberg 4 J. Ross 50

H. Gao 48 M. Lieberman 4 M. Sablik 47

Engineering Research 1993
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