bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analytical Method for Defining Pressure Compensator Dynamics
Authors: Käppi Timo J. , Ellman Asko U. 
Published: November 2021

Abstract
Computer simulation is a powerful and generally accepted practice to carry out research in the area of fluid power. However, accurate parameterization of the component models is required to achieve correct simulation results. The parameters describing the stationary behavior of hydraulic valves are easily available from valve manufacturers’ catalogues. The dynamics are presented typically for the servo valves only. The dynamics of pressure valves are usually more or less unknown even for the manufacturers. Numerical values for simulation purposes are very rarely available.
The lack of information concerning valve dynamics makes the component measurements unavoidable. This is time consuming and costly and the benefits of simulation concept in general are reduced. In this paper a method for defining first order dynamics for the pressure compensator is presented. This method can be used in time-domain simulation of fluid power components and systems. The method is based on the analytical dimensions of valve such as diameter of damping orifice, spring constant and mass.
Pressure compensated mobile valve is measured for method verification. The presented method can be applied to any type of commercially available well damped single-stage pressure valves. It makes the fluid power component parameterization considerably easier and thereby the advantages reached by simulation are increased.
Comparison of Different Viscoelastic Models for Nonlinear Free Vibrations of Moving Belts
Authors: Zu Jean W. , Hou Zhichao 
Published: November 2021

Abstract
Four classical viscoelastic models are adopted to analyze the nonlinear free vibrations of moving belts. The models include Kelvin solid, Maxwell fluid, standard linear solid and Maxwell-Kelvin fluid. Two model-dependent parameters are given for each model. In terms of these parameters, general solutions of the free oscillation responses are given in closed forms for all these models. For the resulting amplitudes and frequencies, numerical simulations are performed to compare these viscoelastic models.
Stability of a Gyroelastic Plate
Authors: Yamanaka K. , Heppler G. R. 
Published: November 2021

Abstract
An model of a gyroelastic thin plate is presented. The equations of motion and boundary conditions are derived when the system is subject to in-plane external loads. It is shown that these systems can display both static instabilities (divergence) and dynamic instabilities (flutter), that the structure of the stability regions depends on the aspect ratio of the plate and that gyroscopic stabilization is sometimes possible.
Analysis and Optimization of Foam Core Mid-Plane Asymmetric Sandwich Beams Under Lateral Loads
Authors: Vinson Jack R. , Satapathy Nihar R. 
Published: November 2021

Abstract
The equations with which to analyze, design and optimize honeycomb sandwich beams subjected to laterally distributed loads are presented. They apply to beams using composite materials and for isotropic materials. Specifically they account for mid-plane asymmetry in order to maximize the structural efficiency, thus providing for differing face materials, ply sequencing and/or thicknesses. Explicit solutions are given for the beam subjected to a uniform lateral load for several boundary conditions. To attain minimum weight, the means to select each face thickness, the core depth and the honeycomb core wall thickness and cell size are given. Localized face dimpling and face wrinkling, using and comparing the results of Heath equation and the Hoff-Mautner equation are included. The effects of transverse shear deformation are also shown. In order to choose the face material and core materials to achieve a minimum weight structure, Factors of Merit are defined for the faces and the core. Various face materials are then compared.
A New Modeling Approach to Reacting Dispersed Flow in Smelting Cyclones
Authors: Modigell M. , Weng M. 
Published: November 2021

Abstract
The present paper proposes a new approach to analyse the conversion of complexly composed particles that are dispersed in a cyclone gas flow at high temperatures. The numeric simulation of flow field and particle trajectories is coupled with a thermodynamic equilibrium calculation which describes the particle reaction progress. First simulation results and the comparison with experimental data are shown in this paper.
Finite Element Simulations of Gas-Liquid Flows With Surface Tension
Authors: Wang Gang 
Published: November 2021

Abstract
The finite-element program, ANSYS/FLOTRAN, has been enhanced at Release 5.7 to predict gas-liquid flows with surface tension. The two-dimensional incompressible Navier-Stokes and energy equations are solved in both Cartesian and axisymmetric geometry. The location of the interface is computed and tracked with the CLEAR-VOF algorithm. Normal and tangential boundary conditions at the interface are enforced through a continuum surface force (CSF) model. This new algorithm is first validated with two model problems: a droplet in equilibrium and an oscillating droplet. For the first problem, the computed pressure value is compared with the theoretical value, whereas for the second problem, the oscillation frequency is compared with both the analytical solution and the experimental data. The computer program is then applied to a number of interesting free surface problems: droplet impacting on a rigid wall, binary droplet collision, flow induced by wall adhesion, and marangoni convection in a rectangular cavity.
Scaled Experiments and CFD Simulations Supporting the Design of the Spallation Neutron Source Mercury Target
Authors: Pointer W. David , Wendel Mark W. , Crye Jason M. , Ruggles Arthur E. , Felde David K. , Jalouk Philip A. , Yoder Graydon L. , Haines John R. 
Published: November 2021

Abstract
A combination of experimental and computational methods is necessary to adequately characterize the flow patterns in the liquid mercury target of the Spallation Neutron Source (SNS). Since liquid mercury is completely opaque and corrosive to many materials, the use of liquid mercury as the working fluid makes complete characterization of the flow field by experiment difficult. Furthermore, flow asymmetries and quasi-periodic instabilities that are observed in early target flow experiments are difficult to capture in computational fluid dynamics (CFD) simulations of the system. Therefore, an experimental program using several scaled experiments is combined with CFD simulation for the design and development of the SNS mercury target.
A Design of Experiment Using Computation Fluid Dynamics for Spool-Type Hydraulic Valves
Authors: Miller Ronald H. , Strumolo Gary S. , Leon Carlos 
Published: November 2021

Abstract
In order to compete successfully in the global market place, manufactures must have the ability to produce high-quality, low-cost products that fully satisfy the customer’s needs. Many analytical techniques have been adopted by these manufactures aimed at improving customer and engineering quality. Nonlinear multivariate systems, however, complicate this process making the determination of controlling factors difficult. Often times, improvements in one area of the process or product compromises the performance in other areas. The Design of Experiments (DOE), pioneered by Taguchi, represents a powerful statistical method to help better understand nonlinear systems with the aim to improve quality and performance in engineering. A DOE using Computational Fluid Dynamics (CFD) is developed to better understand the influences of flow forces on valve design and performance. Geometric control factors for the spool valve are determined, enabling optimization and performance improvements.
Development of an Anti-Interference Swirl Meter Based on Numerical Simulation of Hydrodynamic Vibration
Authors: Fu Xin , Yang Huayong 
Published: November 2021

Abstract
Having the advantages of no motion elements, high reliability, undemanding maintenance and good medium flexibility, the swirl meter has been widely used to measure the gas, liquid and steam in chemical, petroleum as well as processing industries. For the current one-piezoelectric-pressure-sensor swirl meter, however, the measuring error caused by the interference pressure oscillation limits its application in the system where pressure is unsteady, or a noisemaker is nearby. In this paper, the fluid dynamic features inside the channel of the swirl meter are studied numerically and by experiment. The time dependent vortex motions as well as the hydrodynamic vibrations within the channel of the swirl meter are simulated using the CFD approaches of the RNG k-ε model. The computed flow fields indicate that the eccentric motion of vortexes initiates an axisymmetric pressure oscillation within the vortex precession area of the swirl meter. The frequency of the oscillation shifts linearly with volume flow rates. Both the calculated and the measured results prove that the hydrodynamic vibrations on the arbitrary axisymmetric points are equal in amplitude and frequency but with a 180 degree phase difference. By installing differential pressure transducers on such the axisymmetric points, the signals of the vortex pressure oscillations are enhanced, while the interferential signals are suppressed, enabling the anti-interference performance and low-flowrate sensibility of the swirmeter to be effectively improved.
Turbulent Flow Forces on Hydraulic Valves: A Parallel Vortex Simulation Method
Authors: Dimas Athanassios A. , Lottati Isaac , Miller Ronald H. , Strumolo Gary S. , Bernard Peter S. 
Published: November 2021

Abstract
The unique software VORCAT (VORtex Computational Algorithm for Turbulence), which is based on a fast parallel vortex method, is employed to perform a time-accurate simulation of the flow in the spool valve of a pressure regulator from an automotive automatic transmission. The spool valve experiences flow forces which affect its axial motion and radial clearance. The vortex method is based on a parallel implementation of the Fast Multipole Method, and includes a hybrid vortex filament/sheet representation of the flow field, a vortex filament creation model that imitates the physical vortex self-replication process, and a hairpin removal and reconnection mechanism to limit the number and scale of vortical structures to those that are dynamically essential. In this paper, velocity and vorticity distribution results are presented for spool valve openings of 1mm and 0.25mm. The predicted velocity results agree well with corresponding experimental measurements, while the predicted vorticity results correlate well with experimental pressure measurements.
Parallel Optimization Algorithms for Multi-Body Systems in High Performance Computing and Networking
Authors: Hamma Beidi S. , Jiménez José M. , Chehayeb Nassouh A. , Giraud Luc 
Published: November 2021

Abstract
In this paper we present some parallel optimization experiments achieved in ODESIM project, a High Performance Computing and Networking (HPCN) project funded by the European Commission within ESPRIT programme. The project acronym stands for Optimum DESIgn of Multi-Body systems. The project main objective has been the development of a set of software tools for finding optimal designs of MBS for kinematic and dynamic simulation. One part of the work in this project was the definition of parallel optimization algorithms suitable for MBS (Multi-Body Systems) and their implementation in a HPCN framework. In this paper we will present local optimization algorithms as well as some simple global optimization algorithm for MBS simulation.
Simulation of Reynolds’ Color-Dye Experiments on Instability of Circular Pipe Flows: Part 1—Discussion of the Problem
Authors: Kanda Hidesada 
Published: November 2021

Abstract
In previous studies, a conceptual model was constructed for the problem of determining in circular pipes the conditions under which the transition from laminar to turbulent flow occurs. The model is based on the assumption that the shape of the pipe entrance (geometry) governs the critical Reynolds number Rc, such that the minimum value of 2040 was obtained in the case of a straight circular pipe. This implies that the minimum value is obtained when there is no bellmouth attached to the inlet of the pipe. In reality, the normal wall strength, which is generated on the wall, determines a critical Reynolds number. Accordingly, the author assumes that the shape of the bellmouth will lead to the critical Reynolds number of approximately 12,600 observed by Reynolds in his color-dye experiments.
To begin the numerical simulation of Reynolds’ color-dye experiments, it is desirable to validate the model based on the common understanding gained from previous conclusions. As a result, the verification showed the consistency of the model with well-known experimental results, and it was proven why initially disturbed flow becomes laminar flow downstream at Reynolds numbers below the minimum critical value of approximately 2000.
Simulation of Reynolds’ Color-Dye Experiments on Instability of Circular Pipe Flows: Part 2—Definition of the Problem
Authors: Kanda Hidesada 
Published: November 2021

Abstract
Reynolds experimentally studied the flow in circular pipes and then derived the similarity law which is represented by the Reynolds number. The present situation, however, of the study of the transition from laminar to turbulent pipe flows is not obvious. Accordingly, it is desirable to first focus on Reynolds’ color-dye experiments and then to define what the simulation should be. Without the correct definition of the simulation, the study will go astray. By taking the author’s model (described in Part 1) to be valid, a simple definition for the simulation of Reynolds’ color-dye experiments is obtained, which will satisfy the experimental results of Reynolds.
Coupling Between Internal Vortex Shedding and the Axial Acoustic Modes in a Choked Duct Flow: New Experiments
Authors: Petersen Eric L. , Murdock John W. 
Published: November 2021

Abstract
Experiments on vortex shedding within a choked duct and its coupling with the duct’s longitudinal acoustic modes are reported. The vortex shedding and impingement mechanism was produced by a pair of concentric orifice plates placed within the duct. The results of the experiments demonstrate that the frequencies and strengths of the measured acoustic tones depend on the flow velocity, Reynolds number, orifice size, and orifice spacing. A standing wave was produced when the orifice-pair tone was near a longitudinal acoustic mode of the chamber. The oscillation frequency increased slightly with increasing Reynolds number but usually remained within 2-3% of a chamber longitudinal mode. Dual tones and abrupt frequency shifts in singular tones were observed for changes in Reynolds number and/or plate-to-plate spacing. The results of these experiments are part of an ongoing study to better understand the fundamental mechanisms of vortex-induced pressure oscillations within a flow chamber.
Effect of Liquid on a Reciprocating Compressor
Authors: Shiva Prasad B. G. 
Published: November 2021

Abstract
Compressors are intolerant to liquids. Liquids can form inside compressor cylinders by condensation as in refrigerant compressors, or find its place inside cylinders by a gradual or sudden ingestion through the inlet piping in the form of slugs. In reciprocating compressors with inherently large volumetric displacement rates, all modes of ingestion pose a serious problem and can even result in catastrophic failures. This paper describes a simple method of estimating the cylinder pressure and “rod load” (force on the crosshead pin, in compressor terminology) in a double-acting reciprocating compressor. The results indicated that even with moderate volume of liquid present inside the cylinder, the pressure could reach values as high as 4 to 5 times its normal value with a correspondingly higher rod load.
Unsteady Fluid Flow and Force on an Obstruction in a Pipe
Authors: Choe Hwang 
Published: November 2021

Abstract
An unsteady fluid flow in a pipe with an orifice or an obstruction is studied. The velocity in the pipe and the force on the obstruction are calculated numerically. Several different forcing functions are considered for this unsteady flow system: a sinusoidal forcing function, a step forcing function, and a ramp forcing function. The response to the sinusoidal forcing function as a function of frequency for the fluid flow system is the main focus of this paper. The results for this non-linear system are found to be significantly different from those of a linear system. The results and the method of this study may be applied to the calculations of unsteady forces acting on objects such as check valves or probes in a pipe with unsteady turbulent flow.
Validation of the RFG Method for Generating Time-Dependent Inflow Boundary Conditions
Authors: Shi Shaoping , Smirnov Andrei , Celik Ismail 
Published: November 2021

Abstract
A new Random Flow Generation (RFG) (Smirnov et al., 2000b) approach is proposed which can provide turbulent initial or inflow conditions for unsteady flow calculations. This methodology is briefly described. Boundary layer flow with the the Reynolds stresses known from experiments is used to validate the method. The issues of anisotropy and continuity of the fluctuating field are discussed. This approach has been applied for the wake behind a flat plate using large eddy simulation (LES) technique. Good results are obtained as compared to experiments.
Damage Tolerance Analysis of Railroad Tank Cars
Authors: Zhao Wei , Sutton Michael A. , Penã Jose , Hattery Brenda K. , Wang Duan Q. , Hubbard Camden R. 
Published: November 2021

Abstract
The paper summarizes an effort in improving structural integrity of the railroad tank cars. Damage tolerance analysis is performed on a DOT 111A100W1 general purpose tank car. Stress distributions and potential fatigue critical locations are determined using global and local finite element models. Welding residual stresses in an unconstrained TC128-B butt weld are obtained using neutron diffraction technique. Fatigue crack growth analysis under a tank car service load spectrum is carried out and inspection intervals are determined for various postulated initial flaws. Two materials are considered, a generic steel (presumably representing A516-70), and A515 for older tank cars.
Rail Passenger Equipment Collision Tests: Analysis of Structural Measurements
Authors: Severson Kristine J. , Tyrell David C. , Perlman A. Benjamin 
Published: November 2021

Abstract
A two-car full-scale collision test was conducted on April 4, 2000. Two coupled rail passenger cars impacted a rigid wall at 26 mph. The cars were instrumented with strain gauges, accelerometers, and string potentiometers, to measure the deformation of critical structural elements, the longitudinal, vertical, and lateral car body accelerations, and the displacements of the truck suspensions. Instrumented crash test dummies were also tested in several seat configurations, with and without lap and shoulder belts.
The objectives of the two-car test were to measure the gross motions of the car, to measure the force/crush characteristic, to observe the car-to-car interaction, to observe failure modes of the major structural components, and to evaluate selected occupant protection strategies. The measurements taken during the test were used to refine and validate existing computer models of conventional passenger rail vehicles. This test was the second in a series of collision tests designed to characterize the collision behavior of rail vehicles.
The two-car test resulted in approximately 6 feet of deformation at the impacting end of the lead vehicle, and a few inches of deformation at the coupler. The cars remained coupled, but buckled in a saw-tooth mode, with a 15-inch lateral displacement between the cars after the test.
The test data from the two-car test compared favorably with data from the single-car test, and with analysis results developed with a lumped-mass computer model. The model is described in detail. The methods of filtering and interpreting the test data are also included.
Rail Passenger Equipment Collision Tests: Analysis of Occupant Protection Measurements
Authors: Tyrell David , Zolock John , VanIngen-Dunn Caroline 
Published: November 2021

Abstract
The Federal Railroad Administration has been conducting research on occupant protection in train collisions. As part of this research, computer simulations have been performed, passenger seats have been sled tested, and two full-scale collision tests of rail passenger cars have been conducted. The passenger equipment collisions tests that have been performed to date are:
1. Single car impact into a fixed barrier at 35 mph.
2. Two coupled car impact into a fixed barrier at 26 mph.
As part of these tests, the cars were instrumented to measure the deformations of critical structural elements; the vertical, lateral, and longitudinal deceleration of the carbody and trucks; and the suspension displacements. The cars were also equipped with instrumented anthropomorphic test devices (test dummies) in three interior arrangements:
1. Forward-facing unrestrained occupants seated in rows, compartmentalized by the forward seat in order to limit the motions of the occupants.
2. Forward-facing restrained occupants with lap and shoulder belts.
3. Rear-facing unrestrained occupants.
This paper describes the vertical and lateral motions of the cars during the two-car impact test, and discusses their influence on the responses of the instrumented dummies. The lateral motions of the cars appear to have had little influence on the response of the test dummies. The vertical motions of the cars may have had an influence on the forward facing unrestrained test dummies seated in rows. Such experiments were conducted in both the leading and trailing cars, and in both these experiments, the heads of the test dummies rose above the seatback ahead, allowing high neck loads.
Alternative Analyses of Locomotive Structural Designs for Crashworthiness
Authors: Martinez Eloy , Tyrell David 
Published: November 2021

Abstract
Enhanced crashworthiness performance of North American locomotives is proposed by both increasing the design loads on specific structural components or by describing the crashworthiness performance under specific impact conditions. The design loads for a conventional North American locomotive and the description of performance are intended to provide the same level of crashworthiness protection. A generic design was developed to illustrate the types of calculations that can be used to show that the design loads can be supported and the desired level of performance can be met. The performance of the generic locomotive subjected to a collision with a grade crossing object is measured by its ability to prevent penetration of the object into the occupied volume where the crew rides out the collision. The closed form hand calculations apply established structural analysis limit load theory and show the design loads can be supported. The finite element analysis results capture large deformation non-linear behavior and show the desired level of performance is achieved.