bluuebunny/crossref_metadata_2025 huggingface dataset:
Semi‐implicit second order finite volume jet stream
computations
Authors: Tucker P.G. , Long C.A.
Published: September 2004

Semi‐implicit, second order temporal and spatial finite volume
computations of the flow in a differentially heated rotating annulus are
presented. For the regime considered, three cyclones and anticyclones
separated by a relatively fast moving jet of fluid or “jet
stream” are predicted. Two second order methods are compared with,
first order spatial predictions, and experimental measurements. Velocity
vector plots are used to illustrate the predicted flow structure.
Computations made using second order central differences are shown to agree
best with experimental measurements, and to be stable for integrations over
long time periods (>1000s). No periodic smoothing is required to
prevent divergence.
Natural convective heat transfer from a cylinder in an enclosure partly
filled with a porous medium
Authors: Oosthuizen P.H. , Naylor D.
Published: September 2004

Heat transfer from a cylinder placed on the vertical centre‐line
of a square enclosure partly filled with a porous medium that is saturated
with a fluid has been numerically studied. The cylinder is buried in the
porous medium. The horizontal upper surface of the porous medium is separated
from the rest of the enclosure by a horizontal impermeable barrier that is
assumed to offer negligible resistance to heat transfer. The gap between the
barrier and the top of the enclosure is filled with the same fluid as that
with which the porous medium is saturated. The surface of the cylinder is at
a uniform high temperature. The bottom and sides of the enclosure are assumed
to be adiabatic while the horizontal upper surface of the enclosure is
assumed to be kept at a uniform low temperature. The natural convective flows
that occur in the porous medium and in the fluid layer above the barrier have
been assumed to be steady, laminar, two‐dimensional and symmetrical
about the vertical centre‐line of the enclosure. Fluid properties have
been assumed constant except for the density change with temperature which
gives rise to the buoyancy forces. The governing equations have been
expressed in dimensionless form and solved using a finite element procedure.
Results have been obtained for a Prandtl number of 0.7 for a wide range of
the governing parameters. The main aim of the study was to determine how the
mean heat transfer rate from the cylinder is affected by the size of the
fluid gap at the top of the enclosure. The effect of this gap size has been
related to changes in the flow pattern in the porous and fluid
regions.
A finite volume method for the solution of the extrudate swell problem
on unstructured triangular meshes
Authors: Despotis G.K. , Tsangaris S.
Published: September 2004

The extrudate swell phenomenon is analysed by solving, simultaneously,
the Navier‐Stokes equations along with the continuity equation by
means of a finite volume method. In this work, the planar jet flows of
incompressible viscous Newtonian and power‐law fluids for Reynolds
numbers as high as 75 are simulated. The method uses the velocity components
and pressure as the primitive variables and employs an unstructured
triangular grid and triangular or polygonal control volume for each separate
variable. The numerical results show good agreement with previously reported
experimental and numerical results. Shear thickening results in an increase
in swelling ratio, while the introduction of surface tension results in a
describes in swelling ratio.
A comparison of convergence acceleration schemes for eigenfunction
expansions of partial differential equations
Authors: Resende Almeida Alcino , Machado Cotta Renato
Published: September 2004

Different possibilities for the enhancement of convergence rates in
eigenfunction expansions are investigated in the realm of integral transform
solutions for partial differential equations. A representative parabolic
problem is chosen to illustrate two schemes and their combinations; a
filtering technique and an integral balance approach. Numerical results are
presented to confirm the relative merits in each proposed
procedure.
Short Communication boundary‐fitted co‐ordinates for the
asymptotic friction factors and nusselt numbers of laminar flows inside
straight ducts with irregular, singly connected cross‐sections
Authors: Campo Antonio , Morales Juan C.
Published: September 2004

This paper presents a simple computational procedure for the laminar,
fully established velocity and temperature in straight ducts with irregular,
singly connected cross‐sections by virtue of a control volume
discretization of the momentum and energy equations in boundary‐fitted
co‐ordinate systems. The combined procedure has been applied to a
large group of ducts whose cross‐sections possess different levels of
difficulty. The numerical predictions for the pressure drop (friction
factor) and the convective heat transfer coefficient (Nusselt
number) have been reported for a sub‐class of ducts with curved
sides and sharp corners utilizing various grid sizes.
At the Cutting Edge of Manufacturing Technology – Australian
Style
Authors: Haynes Ian , Frost Noel
Published: September 2004

Presents numerous issues faced by Australian manufacturers and
explains the functions of the Queensland Manufacturing Institute,
developed by the government to provide support by way of advice,
training, consultancy services, research and technology available and
gives two examples of successful government assistance.
Winning Strategies for Product Development
Authors: Tong Gregg
Published: September 2004

Presents the winning product development teams from the 1994
American Product Excellence (APEX) Awards. Describes the secrets of
success which includes taking time to understand customer needs and
being “right‐to‐market” instead of
“first‐to‐market”. An overall award was presented to the
team that developed the IBM Thinkpad series of mobile computers.
Toying with success
Authors: Parker Miles
Published: September 2004

Describes recent innovations at a leading toy manufacturer which
introduced DFMA to cut assembly times and costs. States that DFMA Design
for Assembly and Design for Manufacture – can be used as a
brainstorming tool to help designers and engineers make informed
decisions. Suggests that DFMA can be very profitable and a valuable
technique to streamline production.
Screening for chlamydia among adolescents in the UK: a review of policy and practice
Authors: Kane Roslyn , Khadduri Rolla , Wellings Kaye
Published: September 2004

The contribution of the Expert Working Group to combating increasing incidence rates of chlamydia among young people in the UK has been important and timely. The pilot projects, which are currently being evaluated, will shed some light on the feasibility and acceptability of a national screening programme. In the current climate, with increasing prevalence of both symptomatic and asymptomatic infections and low levels of awareness amongst adolescents, detection and treatment of existing infections must be a public health priority.
University campus settings and the promotion of physical activity in young adults: lessons from research in Australia and the USA
Authors: Leslie Eva , Sparling Phillip B. , Owen Neville
Published: September 2004

Describes the decreasing prevalence of physical activity participation over the young adult years and the patterns of difference in the physical activity habits of young men and young women. Physical activity habits during the young adult years are likely to be important influences on habitual physical activity during overall adult life and, consequently, have significant implications for long‐term health outcomes. Tertiary‐education campuses are settings where there exist important yet partially neglected opportunities to influence the physical activity habits of young adults. Uses examples from Australia and the USA are used to characterise relevant contextual and practical aspects of the campus setting and the physical activity promotion opportunities that it may provide. Reviews findings from two campus‐based physical activity intervention studies. In conclusion, identifies a set of issues that require further research.
Identifying potential heavy drinkers in early adolescence
Authors: Lintonen Tomi P. , Konu Anne I. , Rimpelä Matti
Published: September 2004

Based on the Adolescent Health and Lifestyle Survey 1999 in Finland (N= 2,385), this study aimed at identifying characteristics related to heavy drinking in 14‐year‐olds. The characteristics were studied for association with drinking style (abstinence, occasional drinking, recurring drinking, recurring drunkenness). Two‐thirds of the 14‐year‐olds drank alcohol; 10 per cent of boys and 15 per cent of girls reported recurring drunkenness. Factors showing strongest associations with increased drinking were smoking, lack of parental control and high weekly allowance. Drinking among 14‐year‐olds has developed into being a common behaviour. Early adolescent drinking seems associated with a multitude of background and lifestyle factors, all of which may be helpful in identifying drinkers, although not particularly heavy drinkers. The efforts aimed originally at identifying heavy drinkers will probably yield a rather heterogeneous group with regard to their drinking habits. However, all drinking may be considered problematic, e.g. from the legal point of view. As the factors associated with occasional drinking and heavy drinking were the same, no support can be given to the assumption that there exist any specific “risk factors” for heavy drinkingat this early age.
New designs of work groups: applications of empowerment
Authors: Margulies Jeff S. , Kleiner Brian H.
Published: September 2004

Examines new developments in work group design. Autonomous work
groups, also called self‐regulated work groups or self‐managing work
teams, have been described as originating primarily from socio‐technical
work design. The concept of autonomous work groups has also been
described as a more comprehensive application of the methods employed in
quality circles. Both of these examples will be shown to be inaccurate
descriptions of a truly self‐managed work team. Instead, through the
implementation and application of self‐managed work teams, a combination
of socio‐technical design is utilized with a concept that goes far
beyond that of quality circles‐empowerment. Empowerment is the idea that
employees and groups can achieve higher levels of productivity, quality,
and team member satisfaction through delegation of more task‐related
decisions to the team. However, there are considerations in the
implementation of autonomous work groups. These include development of
trust, appropriate status and reward systems, senior management support,
and the effective management of change. Focuses on the changes and
processes that are integral parts of the successful implementation of
empowerment.
A general purpose consensus problem‐ solving model
Authors: Harley William B.
Published: September 2004

Investigates a versatile consensus problem‐solving model developed by the author which gives values a central position. Provides team members with a principle‐centered vision to encourage inspired solution finding. Because the model provides a discipline for the alternate suspension and use of critical judgment, it constructively channels the expression of diverse viewpoints and defuses negative conflict. Discusses 11 steps to the consensus problem‐solving process. Concludes that this process helps a team to manifest the paradoxical attributes of both unity in diversity and patient efficiency.
Satisfaction, sacrifice, surprise:
Authors: Pine B. Joseph , Gilmore James H.
Published: September 2004

The authors describe and explain the progression of economic value, showing that customizing a good turns it into a service, customizing a service turns it into an experience, and customizing an experience turns it into a transformation. Businesses that wish to prosper in the emerging experience economy should begin by mass customizing their goods and services. To determine which products to customize, many companies gather customer satisfaction or “voice of the customer” surveys that use market research techniques to get data. However, these techniques do not go far enough to determine what and where a company should mass customize, because customer satisfaction measures market, not individual customer, satisfaction. The authors conclude by presenting their 3‐S Model that shows the importance of driving up customer satisfaction and driving down customer sacrifice as a foundation for effectively instigating customer surprise.
Are you L.E.A.D.ing your troops?
Authors: Kraines Gerald A.
Published: September 2004

Leadership, at its best, leverages other people’s full potential The L.E.A.D. program follows neither the old command‐and‐control style of management nor the more laissez faire approaches that have emerged. Instead, L.E.A.D. begins with a clear mandate for managers to leverage their people to their highest levels of achievement, as individuals and as a group. The first step involves leveraging employee judgment, then fully engaging them in their work by respecting the psychological contract implied in employment, aligning all employee efforts by clarifying context, and finally developing individual capacity by coaching and mentoring. The L.E.A.D. process can spell the difference between truly outstanding achievements vs. run‐of‐the‐mill practices that achieve far less.
Putting tools to the test:senior executives rate 25 top management tools
Authors: Rigby Darrell K.
Published: September 2004

Eight years ago, Bain & Company launched an annual survey to investigate the actual experience of companies that adopt leading management tools: Which tools are the most popular? How well do they work? And do they continue to deliver results over time? This article presents the answers to these questions, based on the latest (2000) North American survey results. On the one hand, 78 percent of respondents agreed that “Companies that use the right tools are more likely to succeed.” Yet, at the same time, 82 percent agreed that “Most management tools promise more than they deliver.” Senior executives fundamentally believe there are tools that can improve organizational performance, yet experience using these tools has also dampened their enthusiasm for the results. Includes a discussion of the 25 top management tools.
Unlocking shareholder value from shared services
Authors: Mergy Lee , Records Paul
Published: September 2004

Shared service functions such as finance and HR are more important to the success of most corporations today than they ever have been. Yet in many companies, they receive far less executive attention than the business units because shared services are not expected to generate profits. This article proposes that senior executives should require equally high standards for strategic‐planning and profit‐generating initiatives from their shared services as they do from business units. As a case study illustration, the authors describe how Champion International adopted a process to push shared service managers into value‐enhancing initiatives and strategies and how that process helped transform the company’s performance.
Managing process risk: planning for the booby traps ahead
Authors: Buchanan Deborah , Connor Michael
Published: September 2004

Any time a company significantly changes the way it does things, there is "process risk," i.e., the risk that the business will suffer significant financial losses or harm to its reputation as a result of the change. Failure to effectively manage process risk explains why most major change initiatives ultimately fail. Process risk can take several forms. Four commonly observed varieties include performance dips, project frights, process fumbles, and process failures. The authors explore the human and operational process risks and propose precautionary steps that managers can take to circumvent these risks in the future.
Accountancy and corporate property management ‐ A briefing on current and proposed provisions relating to UK corporate real estate
Authors: Evans Michael , French Nick , O’Roarty Brenna
Published: September 2004

Discusses the role of property within corporate organisations and, in particular, discusses the impact of real estate on the balance sheet of UK‐based corporate businesses. Also explains how new and proposed provisions from the Accounting Standards Board (ASB) may affect the way in which property is held and managed in the future. Considers the proposed changes from the viewpoint of the property professional and from an accountancy perspective. Concludes that, in the future, management will be required to apply a greater focus on their property portfolio in order to meet the relevant accounting standards.
Variance in commercial property valuations for lending purposes: an empirical study
Authors: Bretten James , Wyatt Peter
Published: September 2004

Investigates the extent and possible causes of variance in property investment valuations for commercial lending purposes within the UK. A literature review was undertaken and a questionnaire survey was circulated to individuals involved in the commercial property valuation process in order to gauge professional opinion. The survey revealed that the main cause of variance was found to be a result of the individual valuer’s “behavioural influences”. The survey also found that parties to a valuation instruction widely accept the margin of error principle, the legal manifestation of valuation variance, as a test of negligence.
Does corporate real estate create wealth for shareholders?
Authors: Hiang Liow Kim , Ooi Joseph T.L.
Published: September 2004

This study examines the influence of corporate real estate (CRE) on shareholder value using two value‐based measures: economic value added (EVA) and market value added (MVA). We find that CRE has impacted negatively on non‐real estate firms' EVA and MVA in the period 1997‐2001. This happens for the non‐real estate corporations from different industries. Further, the higher the real estate asset intensity, the greater the negative impact on the firms' EVA and MVA. Our results have important implications for the traditional notion that there is a competitive advantage in owning CRE by diversified conglomerates. Specifically, more studies are needed to explore and compare the main reasons and motivations as to why Asian non‐real estate firms are still more involved with real estate activities than their counterparts in Europe and USA even though ownership of CRE appears to destroy shareholders' wealth.
Contagion or interdependence?
Authors: Wilson Patrick , Zurbruegg Ralf
Published: September 2004

This paper examines whether there was contagion from the Thai securitised real estate market to four other prominent Asia‐Pacific property markets. Based on Forbes and Rigobon's methodology for calculating conditional and unconditional correlations, analysis shows that there was some contagion effect from Thailand to Hong Kong and Singapore during the period between early July and late October 1997. However, if the period includes the stock market crisis of late October 1997, there is little evidence for real estate market contagion, as it would seem that the impact of the equity markets were more relevant thereafter, in affecting other financial markets than the property markets themselves.
Governance and optimal financing for asset‐backed securitization
Authors: Fan Gang‐Zhi , Foo Sing Tien , Eng Ong Seow , Sirmans C.F.
Published: September 2004

Asset‐backed securitization (ABS) is an interesting financial innovation whereby debt instruments backed by cash flows generated from income‐producing assets are issued for investment purposes in the capital markets. This study examines the characteristics of ABS transactions in Singapore and evaluates whether proper governance mechanisms have been developed to protect ABS investors. We examined the unique features of the Visor case, such as rental guarantee, large block ownerships of junior bonds, credit enhancement, embedded options, managerial relationships between the SPV and servicers, and critically evaluated the effects of these characteristics on the governance of ABS. Rules on separation of banks' participation in ABS and the accountant's requirement of “clean sale” that affect the ABS structure were also discussed. We also develop a simple information asymmetric model to evaluate the pecking order choice of two different financing methods: collateralized loans and ABS.
The application of intelligent hybrid techniques for the mass appraisal of residential properties
Authors: McCluskey William , Anand Sarabjot
Published: September 2004

Hybrid systems as the next generation of intelligent applications within the field of mass appraisal and valuation are investigated. Motivated by the obvious limitations of paradigms that are being used in isolation or as stand‐alone techniques such as multiple regression analysis, artificial neural networks and expert systems. Clearly, there are distinct advantages in integrating two or more information processing systems that would address some of the discrete problems of individual techniques. Examines first, the strategic development of mass appraisal approaches which have traditionally been based on “stand‐alone” techniques; second, the potential application of an intelligent hybrid system. Highlights possible solutions by investigating various hybrid systems that may be developed incorporating a nearest neighbour algorithm (k‐NN). The enhancements are aimed at two major deficiencies in traditional distance metrics; user dependence for attribute weights and biases in the distance metric towards matching categorical variables in the retrieval of neighbours. Solutions include statistical techniques: mean, coefficient of variation and significant mean. Data mining paradigms based on a loosely coupled neural network or alternatively a tight coupling with genetic algorithms are used to discover attribute weights. The hybrid architectures developed are applied to a property data set and their performance measured based on their predictive value as well as perspicuity. Concludes by considering the application and the relevance of these techniques within the field of computer assisted mass appraisal.
The performance and inflation hedging ability of regional housing markets
Authors: Stevenson Simon
Published: September 2004

The literature concerned with British regional housing markets has been relatively limited, especially in comparison to the research undertaken with regard to the commercial market. This paper aims to redress the balance primarily in two areas. First, the performance of regional housing markets over the period 1983 to 1995 is assessed and compared to comparable returns from the commercial sector and the UK equity and bond markets. The second area of concern is the inflation hedging ability of these markets. While a large number of studies have examined the UK commercial sector, the residential market has been largely ignored. The paper examines the issue using the Ordinary Least Squares (OLS) regression model proposed by Fama and Schwert (1977) and also on a long‐term basis using cointegration techniques. The results are mixed, with some evidence that the residential market provides a hedge, but with little evidence that the commercial market provides protection against inflation. While no evidence was found that either property sector is cointegrated with inflation, there was some evidence of causal relationships. Additionally, in both the performance appraisal and in the inflation tests, substantial differences were found between different regional markets.
Estimation and analysis of the risk premium for commercial property
Authors: Tarbert Heather , Marney John‐Paul
Published: September 2004

This paper has two main aims. First, given that an approximately 2 per cent positive differential of property over gilts appears to be the accepted required risk premium, then it is useful to examine the actual values of ex‐post risk premiums of property over both conventional and index‐linked gilts to determine whether this is achieved. Second, the univariate time series properties of the generated risk premiums are analysed to ascertain if there are any stable forecasting attributes embodied in the first and second moments.
The determinants of capital structure Evidence on UK property companies
Authors: Ooi Joseph
Published: September 2004

Employing the panel data methodology, we examine the capital structure determinants of 83 property companies quoted in the UK. The empirical test reveals how the debt‐equity structure of the companies is influenced by the various firm‐specific attributes and macro‐economic factors. In particular, the evidence shows that asset structure, business orientation, and the level of involvement in property development are significant determinants of the corporate debt policy of property companies. Financial distress consideration also has a significant influence. In addition, the empirical evidence shows that corporate property managers take into consideration the prevailing market sentiment and borrowing costs when making the debt‐equity choice. Corporate performance and tax burden, however, do not appear to have any significant effect on the capital structure decision of property companies.
Estimating the market value of a proposed townhouse development
Authors: Janssen Christian , Yang Zan
Published: September 2004

An appraisal by an accredited appraiser is often necessary before a proposed development can receive a commitment for financing from a financial institution. Such pre‐construction appraisals are often more difficult to complete than those where the subject property is already developed and accessible for inspection. In this article we are performing a valuation of a proposed townhouse complex prior to its construction. Hedonic estimation is used to estimate the market value of the proposed development. The estimated value of the complex as a whole, and of the individual units, is compared to the prices obtained as the townhouses were built and sold. Insights with respect to the feasibility of the approach for the estimation of the gross retail value of proposed developments are discussed.
Learning from death
Authors: Cowan P. Jane
Published: September 2004

Reporting a death to the coroner by a doctor is not a statutory duty. It is, however, expected good practice. This article discusses some of the concerns arising out of current everyday practice that can lead to problems for doctors and their employing organisations. The author considers the importance of risk management, clinical audit and clinical governance in identifying what systems may need to be addressed within hospital and primary care trusts to ensure that deaths arising out of, or occurring during, medical care are investigated appropriately. As part of risk management and controls assurance, NHS Trusts should be able to demonstrate that lessons are learnt from adverse outcomes. This article explores the roles of postgraduate tutors, risk managers and the protection organisations in promoting good practice from the start of a doctor’s career.
The Death Watch Beetle Case
Authors: Murrells Paul
Published: September 2004

Reviews a recent case in the Official Referees Court where it was
alleged that a surveyor did not give sufficient warning about the severe
damage that the death watch beetle can do to a timber‐framed house.
Innovate to Accumulate
Authors: West Graham
Published: September 2004

Read just about any literature, advertisement or media article,
written within the last decade, describing a product, service or
organization, and you can be sure of at least one inclusion of the word
“innovation”. Sadly, the word “innovation”, in
recent usage, has become so hackneyed it seriously runs the risk of
metamorphosizing into an expression of a doubtful quality. This
interview with Phil Robson, Managing Director, NIS Ltd, UK, explores
this role and meaning of the “innovation” within the context
of manufacturing industry.
A bem analysis for transient conduction—convection problems
Authors: Lim J. , Chan C.L. , Chandra A.
Published: September 2004

A boundary element method (BEM) formulation for the solution
of transient conduction‐convection problems is developed in this
paper. A time‐dependent fundamental solution for moving heat source
problems is utilized for this purpose. This reduces the governing parabolic
partial differential equations to a boundary‐only form and obviates
the need for any internal discretization. Such a formulation is also expected
to be stable at high Peclet numbers. Numerical examples are included to
establish the validity of the approach and to demonstrate the salient
features of the BEM algorithm.
An asymptotic solution for the singularity at the angular point of the
lid driven cavity
Authors: Störtkuhl T. , Zenger C. , Zimmer S.
Published: September 2004

In this paper, we analyse the behaviour of the solution of the
Navier—Stokes equations near the corner of the driven cavity where the
moving band touches the wall. At this point, the solution is singular. Since
the singularity does not depend on the Reynolds number, it is sufficient to
study the problem in the case of infinite viscosity, which is governed by the
Stokes equations. We present an analytical asymptotic solution near the
corner. Furthermore, numerical results are given, which were gained by an
efficient multigrid algorithm. We will see that, for decreasing meshsize, the
numerical solution converges to the derived analytical solution near the
corner.
Finite element simulation of laser surface treatments including
convection in the melt pool
Authors: Picasso M. , Hoadley A.F.A.
Published: September 2004

A two‐dimensional, macroscopic, stationary, finite element model
is presented for both laser remelting and laser cladding of material
surfaces. It considers, in addition to the heat transfer, the important
fluid motion in the melt pool and the deformation of the liquid—gas
interface. The velocity field in the melt is driven by thermocapillary forces
for laser remelting, but also by forces due to powder injection for laser
cladding. For a given velocity field within the liquid region, the stationary
enthalpy (or Stefan) equation is solved. An efficient scheme allows
the LU decomposition of the finite element matrix to be performed only once
at the first iteration. Then, the velocity is updated using the Q1—P0
element with penalty methods for treating both the
incompressibility condition and the slip boundary conditions. Numerical
results for three different processing speeds for both laser remelting and
laser cladding demonstrate the efficiency and robustness of the numerical
approach. The influence of the thermocapillary and powder injection forces on
the fluid motion and subsequently on the melt pool shape is seen to be
important. This kind of calculations is thus necessary in order to predict
with precision the temperature gradients across the solidification interface,
which are essential data for microstructure calculations.
Enthalpy gradient methods for capturing latent heat in phase change
simulations using biquadratic isoparametric finite elements
Authors: Pittman J.F.T. , Whitham G.P.
Published: September 2004

Methods that use spatial gradients of enthalpy to evaluate effective
specific heats and capture latent heat effects in phase change problems have
been used successfully in finite element formulations based on linear
interpolation. In view of the greater geometrical flexibility and efficiency
of biquadratic isoparametric elements, it is of interest to assess the use of
the methods with these elements. In comparisons with an accurate
semi‐analytic solution for a test problem, it is shown that the
enthalpy gradient methods with quadratic interpolation are prone to error. A
new procedure is proposed that uses bilinear sub‐elements for
enthalpy, formed by subdivision of the biquadratic temperature elements. This
is shown to be accurate and robust, for phase change intervals as small as
0.02°C.
A multigrid method for the compressible Navier—Stokes equations
coupled to the k—ε turbulence equations
Authors: Steelant J. , Dick E.
Published: September 2004

The steady compressible Navier—Stokes equations coupled to the
k—ε turbulence equations are discretized within a
vertex‐centered finite volume formulation. The convective fluxes are
obtained by the polynomial flux‐difference splitting upwind method.
The first order accurate part results directly from the splitting. The second
order part is obtained by the flux‐extrapolation technique using the
minmod limiter. The diffusive fluxes are discretized in the central way and
are split into a normal and a tangential contribution. The first order
accurate part of the convective fluxes together with the normal contribution
of the diffusive fluxes form a positive system which allows solution by
classical relaxation methods. The source terms in the low‐Reynolds
k‐ε equations are grouped into positive and negative terms. The
linearized negative source terms are added to the positive system to increase
the diagonal dominance. The resulting positive system forms the left hand
side of the equations. The remaining terms are put in the right hand side. A
multigrid method based on successive relaxation, full weighting, bilinear
interpolation and W‐cycle is used. The multigrid method itself acts on
the left hand side of the equations. The right hand side is updated in a
defect correction cycle.
Stability characteristics of time integration schemes for finite element
solutions of conduction‐type problems
Authors: Comini G. , Manzan M.
Published: September 2004

Stability characteristics of two‐level, time‐integration
algorithms are investigated, with particular reference to explicit schemes.
Conditions for stability are expressed on the basis of algebraic estimates of
the eigenvalues associated with the amplification matrices of the algorithm.
The use of automatic symbolic manipulators allows an extension of these
estimates to higher order and multidimensional elements. Eigenvectors are
also evaluated algebraically and the resulting fundamental mode shapes are
related to the onset of instabilities.
Fluid flow and heat transfer in a laminar radial impinging jet
Authors: Chakraborty S. , Sengupta S.P. , Biswas G.
Published: September 2004

From the solution of full Navier—Stokes and energy equations, the
development of the flow field and heat transfer characteristics in a radial
jet reattachment flow have been analysed. The influence of Reynolds number of
re‐attachment length for the case of steady laminar flows has been
determined. However, beyond a Reynolds number of 250, the flow field becomes
unsteady and has been found to have a periodic nature. This periodic flow
has been found to persist up to a Reynolds number of 750. The periodicity has
been characterized by the Strouhal number which shows a slight but continuous
variation with Reynolds number around a value of 0.12. The point of maximum
heat transfer is within the re‐attachment zone in the range of Reynolds
numbers studied.
Alternative designs towards thermal optimization of coated valves using
space‐time finite elements
Authors: Zrahia Uzi , Bar‐ Yoseph Pinhas
Published: September 2004

Heat transfer and stress analysis in metallic and coated exhaust valves
are performed by an adaptive space‐time finite element method. Results
indicated that coatings of ordinary thickness cannot protect a coated valve
operating in an uncooled engine. A new approach for designing the inner
geometry of the metallic part in a coated hollow valve is presented. The
purpose of the cavity is changed from cooling to insulating.
Controlling the valve temperature and the heat flows out is done by changing
the geometry of the cavity. The optimum is sought between the hollow geometry
of the valve and its coating thickness while the outer geometry is that of an
ordinary valve. Exhaust valves with optimal geometry are presented. A
reduction of 40% of the heat flows out is obtained, compared to the
heat flows out from a metallic valve operating in a cooled engine. By
comparison, reduction of the heat flows out from a coated, ordinary geometry
valve amounts to only 20%.
Heat transfer in differentially heated non‐newtonian cavities
Authors: Pericleous K.A.
Published: September 2004

The flow development and heat transfer in a differentially heated cavity
containing a non‐Newtonian fluid is studied using CFD techniques.
Investigations are made for a fluid obeying a power‐law type
behaviour, for a nominal Rayleigh number of 105. Both dilatant and
pseudoplastic regimes are considered and the Nusselt number is obtained for a
range of power‐law index values. The results, given in a graphical and
tabular form, suggest that deviations from Newtonian stress‐strain
behaviour can lead to large changes in overall heat transfer. These changes
are due to the behaviour of the wall boundary layers. In the dilatant, or
shear‐thickening regime, the isothermal wall layers are thick and
slow‐moving; as a consequence, buoyancy induced flow affects the
whole of the cavity volume. In contrast, the pseudoplastic (or
shear‐thinning) regime leads to thin, fast‐moving wall
layers whose effect does not propagate to the core of the cavity which
remains stagnant. This behaviour, which is directly attributable to the local
value of the fluid viscosity, causes the average Nusselt number to decrease
with the power‐law index, n. Pseudoplastic fluids are
therefore better at conducting heat than Newtonian fluids, and conversely
dilatant fluids are worse. The information contained in this paper is of
general interest to workers in heat transfer, but is more specifically
relevant to researchers in non‐Newtonian fluids. Example applications
include biotechnology, where close temperature control of bio‐cultures
in enclosed vessels is required, the food processing industry, the metals
casting industry and areas where heat transfer in fine suspensions is
required.
Transient and steady heat conduction using an adaptive finite element
cad‐based approach
Authors: Löhner R. , McAnally J.
Published: September 2004

A new heat transfer simulation capability is described.
Non‐traditional features of this capability include: a seamless link
to CAD‐CAM for rapid problem specification/description, integrated
automatic grid generator tools for rapid mesh generation, nonlinear
and/or varying material properties, source‐terms and boundary
conditions, a one‐element type approach for simplicity and efficiency,
automatic self‐adaptive mesh refinement and coarsening with accurate
error estimation, heavy reliance on iterative solvers, and on‐line
display on workstations for immediate visualization and user feedback. These
innovations are documented on several examples that demonstrate the
usefulness of the developed capability.
Numerical computation of laminar flow in a heated rotating cavity with
an axial throughflow of air
Authors: Long C.A. , Tucker P.G.
Published: September 2004

A heated rotating cavity with an axial throughflow of cooling air is
used as a model for the flow in the cylindrical cavities between adjacent
discs of a high‐pressure gas‐turbine compressor. In an engine
the flow is expected to be turbulent, the limitations of this laminar study
are fully realised but it is considered an essential step to understand the
fundamental nature of the flow. The three‐dimensional,
time‐dependent governing equations are solved using a code based on
the finite volume technique and a multigrid algorithm. The computed flow
structure shows that flow enters the cavity in one or more radial arms and
then forms regions of cyclonic and anticyclonic circulation. This basic flow
structure is consistent with existing experimental evidence obtained from
flow visualization. The flow structure also undergoes cyclic changes with
time. For example, a single radial arm, and pair of recirculation regions can
commute to two radial arms and two pairs of recirculation regions and then
revert back to one. The flow structure inside the cavity is found to be
heavily influenced by the radial distribution of surface temperature imposed
on the discs. As the radial location of the maximum disc temperature moves
radially outward, this appears to increase the number of radial arms and
pairs of recirculation regions (from one to three for the distributions
considered here). If the peripheral shroud is also heated there appear
to be many radial arms which exchange fluid with a strong cyclonic flow
adjacent to the shroud. One surface temperature distribution is studied in
detail and profiles of the relative tangential and radial velocities are
presented. The disc heat transfer is also found to be influenced by the disc
surface temperature distribution. It is also found that the computed Nusselt
numbers are in reasonable accord over most of the disc surface with a
correlation found from previous experimental measurements.
Simulation and analysis of a main steam line transient with isolation valves closure and subsequent pipe break
Authors: Stevanovic V. , Studovic M. , Bratic A.
Published: September 2004

Simulation and analysis of a real main steam line break transient at the
Thermal Power Plant Drmno are presented. The main events of the transient
were the closure of isolation valves in front of a high pressure turbine, an
opening of a by‐pass line, and subsequent pipe break in front of
isolation valves. Intensive pressure waves were generated and they propagated
through the pipe network of the steam line, causing high fluid dynamic forces
on the structure. The transient has been simulated by the computer code
TEA‐01, based on the Method Of Characteristics with three
characteristic directions. Several main steam line boundary conditions have
been modelled and verified. Numerical results are compared with plant data
logger records. Simulation has been performed for various scenarios in order
to investigate the plant behaviour sensitivity on the boundary conditions.
The phenomenology of the pressure waves propagation and the influence of the
boundary conditions on these processes are described in detail, as well as
fluid dynamic forces during the closure of isolation valves and subsequent
pipe break in a section of the steam line in the vicinity of the pipe
break.
Computational Investigation of Cobra probe operation
Authors: De Guzman M.M. , Fletcher C.A.J. , Hooper J.D.
Published: September 2004

The detailed flow behaviour around a four—hole Cobra Pitot pressure
probe, developed by the Commonwealth Scientific and Industrial Research
Organization, Australia, (CSIRO), to determine the pressure and the
velocity components in three dimensional single‐phase/multi‐phase fluid flow, is investigated computationally. The incompressible steady state Navier—Stokes
equations are solved numerically using a general purpose computational fluid
dynamics (CFD) code developed at CANCES. Computational
results are presented for representative probe pitch and yaw angles at a
Reynolds number = 2 × 103, emphasising the pressure
distribution and flow separation patterns on the probe tip adjacent to the
pressure ports. Quantitative comparison of the computational simulation to
experimental results is done by comparing experimental calibration data to
numerically computed pressure responses. The topological features of the near
tip flow behaviour are visualised using critical point concepts and three
dimensional streamlines. Additional qualitative comparison to experiment is
discussed using data from a preliminary experimental investigation using
surface oil film visualisation techniques, where available. Conclusions are
drawn concerning the near tip flow behaviour, the good level of agreement
between the numerical results and experimental data and the effectiveness of
using a computational analysis to provide accurate detail useful for
engineering design purposes.
Efficient shock capturing for isentropic flows using arithmetic
averaging
Authors: Glaister P.
Published: September 2004

A shock capturing scheme is presented for the equations of isentropic
flow based on upwind differencing applied to a locally linearized set of
Riemann problems. This includes the two‐dimensional shallow water
equations using the familiar gas dynamics analogy. An average of the flow
variables across the interface between cells is required, and this average is
chosen to be the arithmetic mean for computational efficiency, leading to
arithmetic averaging. This is in contrast to usual ‘square root’
averages found in this type of Riemann solver where the computational expense
can be prohibitive. The scheme is applied to a two‐dimensional
dam‐break problem and the approximate solution compares well with
those given by other authors.
Natural convection heat transfer around two heated cylinders in an
isothermal enclosure including the effect of wall conductance
Authors: Lacroix Marcel , Joyeux Antoine
Published: September 2004

A numerical study has been conducted for natural convection heat
transfer for air around two vertically separated horizontal heated cylinders
placed inside an isothermal rectangular enclosure having finite wall
conductances. The interaction between convection in the fluid filled cavity
and conduction in the walls surrounding the cavity is investigated. Results
have been obtained for Rayleigh numbers (Ra) between 103
and 106, dimensionless wall thickness (W)
between 0.5 and 1.375 and dimensionless wall‐fluid thermal
conductivity ratio (α) between 0.01 and 5.0.
The results indicate that wall heat conduction reduces the average
temperature differences across the cavity, partially stabilizes the flow, and
decreases natural convection heat transfer. The overall heat transfer
coefficient for both cylinders is correlated with CRan for different
W and α.
Numerical realization of blow‐up spiral wave solutions of a
nonlinear heat‐transfer equation
Authors: Dimova Stefka N. , Vasileva Daniela P.
Published: September 2004

The problem of finding the possible classes of solution of different
nonlinear equations seems to be of a great importance for many applications.
In the context of the theory of self‐organization it is interpreted as
finding all possible structures which arise and preserve themselves in the
corresponding unbounded nonlinear medium. First, results on the numerical
realization of a class of blow‐up invariant solutions of a nonlinear
heat‐transfer equation with a source are presented in this article.
The solutions considered describe a spiral propagation of the inhomogeneities
in the nonlinear heat‐transfer medium. We have found initial
perturbations which are good approximations to the corresponding eigen
functions of combustion of the nonlinear medium. The local maxima of these
initial distributions evolve consistent with the self‐similar law up
to times very close to the blow‐up time.
Numerical studies of mixed recirculatory flow in annuli of stationary
and rotating horizontal cylinders with different radius ratios
Authors: Lee T.S.
Published: September 2004

Mixed recirculatory flow in the annuli of stationary and rotating
horizontal cylinders were studied numerically. A set of distorted
‘false transient’ parameters were introduced to speed up the
steady state solution of the unsteady vorticity, energy and stream
function—vorticity equations. The inner cylinder of the annuli is
assumed heated and rotating at Reynolds numbers that exclude the effects of
centrifugal acceleration and three‐dimensional Taylor vortices. The
Prandtl number considered is in the range of 0.01 to 1.0 and Rayleigh number
in the range of 102 to 106. Radius ratios of the cylinders
considered are 1.25, 2.5 and 5.0. For a radius ratio of 2.5, inner cylinder
rotation in the Reynolds number range of 0 to 1120 was considered. Vertical
eccentricities in the range of ±2/3 were studied for cases of the
rotating inner cylinder. Numerical experiments show that the mean Nusselt
number increases with Rayleigh number for both cases of concentric and
eccentric stationary inner cylinder. At a Prandtl number of order 1.0 with a
fixed Rayleigh number, when the inner cylinder is made to rotate, the mean
Nusselt number decreases throughout the flow. At lower Prandtl number of the
order 0.1 to 0.01, the mean Nusselt number remained fairly constant with
respect to the rotational Reynolds number.