bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing a decision‐making framework for implementing purchasing synergy: a case study
Authors: Smart Alan , Dudas Andreas
Published: January 2007

Purpose

The purpose of this paper is to report on research undertaken within a European‐based airline services firm. As a result of pressures within the airline industry the firm embarked on a cost reduction programme, recognising the need to achieve more synergy from its procurement spend, located in semi‐autonomous business units (BUs). The paper describes sequentially the two stages of the author's involvement in the project and the outputs and results realised.

Design/methodology/approach

The aim was to design a practical tool, based on academic inputs, which could be used by the business to achieve purchasing synergy. The research is reported in a case study format and develops an original mixed method approach. This approach combines interviews, a focus group, cognitive mapping and portfolio analysis and leads to the production of a decision‐making framework for implementing purchasing pooling.

Findings

The results illustrate that prior to the study, procurement was highly fragmented with little co‐ordination between BUs. The company needed to standardise many of its item specifications to facilitate purchasing pooling. A hierarchy is created as a valuable tool for understanding the various and conflicting factors in item selection for pooling initiatives. In addition, four purchasing strategies are identified, to support synergy in the firm.

Practical implications

The decision‐making framework developed for the business is used to illustrate how the firm achieved purchasing synergy across its BUs. The approach can similarly be adopted in organisations with a high level of fragmentation in their spend.

Originality/value

The research demonstrates the value of applying academic knowledge and multiple methods in creating practical solutions for managers. It also addresses some of the weaknesses identified in using single methods of analysis such as portfolios.
Relationship benefits in an internet environment
Authors: Colgate Mark , Buchanan‐Oliver Margo , Elmsly Ross
Published: January 2007

Purpose

The notion of relationships has been shown to be a worthwhile strategy in many service industries. This coupled with the rapid development of the internet means that it is now possible (and even beneficial) to implement internet based relationship management programs. Given the importance of this issue this paper seeks to understand the relational benefits that consumers receive in an internet environment relative to the benefits consumers receive in a traditional environment i.e. face‐to‐face.

Design/methodology/approach

Results are derived from 15 in‐depth interviews (10 from the internet context and 5 from the traditional context) and over 200 quantitative surveys.

Findings

The relationship benefit of “history” appears in both samples which was missing from the original study on relationship benefits. Findings also show that there are differences between the internet group of customers and the traditional customers in respect to the perceived relational benefits. In particular internet customers appear to receive lower levels of the confidence benefit.

Research limitations/implications

We must be careful as these results may be context specific – one company from one industry. Future research must further investigate the ability of the internet to create and sustain relationships. The concept of history seems to be a potent one – how can firms use this newly discovered relationship benefit?

Practical implications

Ultimately internet based relationships are sufficiently different from traditional relationships to require specialized management attention. Managers must pay particular attention to the results which indicate loss of confidence and the need for the personal touch.

Originality/value

First piece of research to look at relationship benefits in the internet context.
The added value of web innovation for customer satisfaction
Authors: van Birgelen Marcel , Ghijsen Paul , Semeijn Janjaap
Published: January 2007

Purpose

Recent studies have explored the effects of e‐service quality on satisfaction and loyalty of online customers by extending and supplementing traditional service quality frameworks. This research proposes a combination of traditional service quality and e‐service quality frameworks. The central question focuses on how to assess the added value of the web as a service innovation for a traditional service. The setting of the study is a traditional‐style barbeque delivery service with a recently installed advanced web‐initiated order entry facility now used by a majority of the customers.

Design/methodology/approach

An empirical, survey‐based cross‐sectional study on web‐initiated customer experiences of an in‐home catering service, involving barbeque food items and cooking equipment.

Findings

Findings indicate that adding an innovative e‐channel to a traditional business process does not automatically translate to a higher customer satisfaction. Only limited significant effects were found from online ordering on overall satisfaction in contrast to the effect of traditional service dimensions.

Research limitations/implications

Further research is needed on the joint analysis of e‐services and traditional services.

Practical implications

E‐service dimensions appear to have a limited impact on overall satisfaction in a traditional business context.

Originality/value

This is one of the first empirical studies combining both traditional and e‐service dimensions and relating them to customer satisfaction.
Service innovation and customer choices in the hospitality industry
Authors: Victorino Liana , Verma Rohit , Plaschka Gerhard , Dev Chekitan
Published: January 2007

Purpose

The purpose of this paper is to understand the impact service innovation has on customers' choices within the hotel and leisure industry. The paper also discusses the influence of the creation of new services on both service development and operational strategy.

Design/methodology/approach

The analysis is based on a national survey of approximately 1,000 travelers in the United States, using a web‐based data acquisition approach. The travelers are segmented by reason of travel (business or leisure), and discrete choice analysis is applied to model customer preferences for various hotel service innovations.

Findings

Overall, the study finds that service innovation does matter when guests are selecting a hotel, with type of lodging having the largest impact on a customer's hotel choice. In addition, service innovation is found to have a larger influence on choices when guests are staying at economy hotels rather than mid‐range to up‐scale hotels. Also, leisure travelers were found to be more influenced by innovative amenities such as childcare programs and in‐room kitchenettes than business travelers.

Practical implications

The understanding of customers' choices allows managers to better design their service offerings and formulate corresponding operational strategies around customer needs.

Originality/value

This paper examines the addition of innovation to the hotel service concept and is an excellent tool for managers deciding on which innovations to implement.
The role of guides in artistic industries
Authors: Surlemont Bernard , Johnson Colin
Published: January 2007

Purpose

The haute‐cuisine industry must cope with two, apparently antagonist demands from customers: providing reliable advice about the choice of restaurant, while concurrently preserving the “magic of discovery” and creativity every haute‐cuisine restaurant should provide. This paper has the objective of analysing how the Michelin guide “star system” operates as a “signalling device” in the industry, and handles these two market requirements. The research also explores how secrecy contributes to preserve chefs' creativity for the benefit of customer satisfaction.

Design/methodology/approach

The research is derived from 20 exploratory field interviews of chefs belonging to the “star system” in France, Switzerland and the UK.

Findings

Field research and analysis reveal the pressure to minimize type II errors, i.e. of selecting restaurants that do not merit inclusion and, consequently, increase type I errors. This behaviour explains the stability, reliability and consistency of the system.

Research limitations/implications

Further research is needed to analyse the extent to which the phenomenon observed in the haute‐cuisine industry is manifest in other artistic (i.e. fashion) or hospitality (i.e. hotels) related sectors.

Practical implications

There is no unique route to the star system. The best way for chefs to increase the odds to get promoted is to focus on quality, develop their own style and be patient. The policy of the Michelin guide opens the door for competing guides willing to take more risk of type I errors.

Originality/value

This exploratory research is the first attempt to analyse the role of gastronomic guides in the haute‐cuisine sector.
What works, and why, in business services provision for SME: insights from evolutionary theory
Authors: Caniëls Marjolein C.J. , Romijn Henny A.
Published: January 2007

Purpose

Programmes providing services for small‐ and medium‐sized enterprises are important. Yet, quality and impact of many of these programmes lag behind expectations. This paper attempts to shed light on the reasons behind this disappointing state of affairs.

Design/methodology/approach

Modern theories of innovation and services marketing management are adopted as a conceptual framework, because these theories generate major insights about how business services should ideally be provided. The usefulness of this framework for analysing business service programmes is demonstrated through its application to one particular programme, the small business service (SBS) in the UK.

Findings

Using this approach, the paper identifies several key issues. Major weaknesses in programme structure and implementation practices emerge, mainly revolving around customer focus, incentive problems and organisational issues, and the lack of a systems perspective.

Research limitations/implications

Given the suitability of the framework for the analysis of our case, it could also prove to be a promising tool for analysing business support programmes in other settings.

Practical implications

Managerial priorities for improvement in the UK emerge. There is a need to improve the incentives facing boundary‐spanning staff. This should be backed up by further organisational reform, to address the fragmentation plaguing the current system.

Originality/value

The methodological approach, of viewing practice in a SBS programme through a theoretical lens, is novel. It could be a useful supplement to conventional performance and impact assessments that are more factual in nature.
The impact of customer relationship characteristics on customer switching behavior
Authors: Pablo Maicas Lopez Juan , Polo Redondo Yolanda , Sese Olivan Fco. Javier
Published: January 2007

Purpose

The purpose of this research is to show how relationship marketing has recognized the importance of building long‐term relationships in increasing firms' profitability and guaranteeing their future viability. Owing to the damaging effects that customer switching behavior could have on the development of successful relationships, understanding customers' switching decisions can represent a key step in the process of establishing, developing and maintaining successful relational exchanges. The current study aims to contribute in this direction by introducing the heterogeneity of customers in their relationship characteristics (depth, length and breadth) into the analysis of customers' propensity to switch service providers.

Design/methodology/approach

The data set used to carry out this study has been obtained from a panel survey (Home Online) of technology users in the United Kingdom, and the proposed hypotheses are tested on the fixed‐line telephone sector using logistic regression. This technique associates the relationship characteristics with the probability that a switch in suppliers will take place.

Findings

The results obtained show that the length, depth and breadth of relationships help to determine customers' propensity to switch fixed‐telephone suppliers. Customers who maintain a long‐lasting relationship with the firm (length), use the service more (depth), and invest in complementary services (breadth) will be less predisposed to switch.

Practical implications

With regard to recommendations for practitioners, the paper highlights the need for firms to renew both acquisition and retention strategies in order to take individual customer information into account. This should help them to identify and retain the most valuable customers and to optimally allocate marketing resources (from switching‐prone to non‐switching‐prone customers).

Originality/value

The main contribution of the paper is to consider relationship characteristics in the analysis of customer switching behavior. This research shows that the heterogeneity observed in the depth, length and breadth of customer‐firm relationships explains the differences in the propensity to switch service providers.
Linking a service‐driven market orientation to service quality
Authors: Voon Boo Ho
Published: January 2007

Purpose

The purpose of this research is to empirically develop a service‐driven market orientation construct and test its relationships with service quality.

Design/methodology/approach

The researcher employs Critical Incident Technique to generate items for the survey instrument. Then, the quantitative‐based descriptive research uses structured questionnaires to capture the perceptions of 558 university students from Malaysia which are used to understand the nature of the customer‐perceived market orientation and its relationship with service quality.

Findings

The results show that the service‐driven market orientation (SERVMO) that consists of six components (customer orientation, competitor orientation, interfunctional orientation, performance orientation, long‐term orientation, and employee orientation) has a significantly strong and positive relationship with service quality.

Research limitations/implications

The SERVMO scale is developed using data from the higher education sector and is yet to be validated in other industries.

Practical implications

The proposed strategic construct and current findings on its relationships with service quality provide practical insights for service managers to monitor their service orientation and enhance service quality.

Originality/value

The newly developed SERVMO scale is originally derived from the customer perception data in the Malaysian higher education sector.
Service expectations of older generation Y customers
Authors: Jin Ma Yoon , Niehm Linda S.
Published: January 2007

Purpose

The purpose of this research is to examine the relationship of older Generation Y (Gen Y) customers' (18‐27) shopping orientations to their expectations for retail services. It also seeks to assess the importance and impact of service expectations and perceptions on customer satisfaction and loyalty when shopping for apparel in different types of retail outlets.

Design/methodology/approach

Three different retail settings (department, specialty, and discount stores) were examined with parallel lists of retail service‐related questions using a convenience sample of older Gen Y female customers. Descriptive analysis, exploratory factor analysis, F‐tests, and regression analysis were employed.

Findings

Shopping orientations were related to older Gen Y customers' expectations for retail services and patronage in all three apparel retail settings. The modified SERVQUAL scale represented one grand service construct in each retail setting. Older Gen Y customers' expectations for service differed by store type, and their service expectations, service perceptions, and service quality were related to retailer satisfaction and store loyalty.

Research limitations/implications

Generalizability of findings may be limited as the study was conducted with female older Gen Y customers shopping for a singular apparel category.

Practical implications

This study illuminates how retail services create value and satisfaction for older Gen Y customers. Results aid in development of service strategies and training programs by type of store outlet.

Originality/value

The study contributes to the scant literature concerning service quality and service expectations for female older Gen Y customers.
Service recovery: a naturalistic decision‐making approach
Authors: Thwaites Edwin , Williams Christine
Published: January 2007

Purpose

The purpose of the paper is to discuss approaches to decision making used in the emergency services and to relate these to decision making in service encounters in the tourism and leisure sector.

Design/methodology/approach

The paper is a conceptual discussion paper that canvasses a range of issues in service encounters, especially the problems of empowerment and service recovery. Although a structured approach to service recovery (often involving 100 per cent guarantees) is popular in the tourism and leisure industry, this precludes spontaneity in solving customers' problems and returning them to a satisfied state. The paper notes that managers have little guidance on how such spontaneity can be effectively accomplished.

Findings

The paper argues that much can be learned from the “naturalistic decision making” (NDM) of emergency decision‐makers. The paper therefore provides an assessment of how NDM could be utilised in the services sector.

Practical implications

Training frontline staff in NDM is a means of improving service recovery, and this has implications for recruitment, retention, and staff training. It also provides a justification for trusting experienced frontline staff members.

Originality/value

The study offers a different perspective on decision making in service situations.
Web site performance measurement: promise and reality
Authors: Welling Ray , White Lesley
Published: January 2007

Purpose

The purpose of this research is to examine the web site performance‐measurement activities of a range of businesses and to determine whether there are common measures that can be successfully applied to rate the performance of corporate web sites.

Design/methodology/approach

Qualitative interviews are conducted with web site managers of 25 businesses, exploring web site activities and performance measures used.

Findings

The study demonstrates that web site performance measurement is largely idiosyncratic and/or completely ignored. Retailing and business‐to‐business companies are more likely to use performance measures (including sales revenue and web‐analytics programs) to determine the value of a web site to the business.

Research limitations/implications

The study covers a broad spectrum of company types and sizes, mainly based in Australia, but did not focus on the use of the internet by specific industries – such as retailing or financial services.

Practical implications

The study should encourage managers to measure the financial and non‐financial contributions made by corporate web sites to the overall performance of a business.

Originality/value

The paper provides insight into the current lack of standards in web site performance measurement and the need for the development of standards in this area.
Modelization of combined radiative and conductive heat transfer in three‐dimensional complex enclosures
Authors: Guedri Kamel , Naceur Borjini Mohamed , Farhat Habib
Published: January 2007

Purpose

To provide a finite volume code, based on Cartesian coordinates, for studying combined conductive and radiative heat transfer in three‐dimensional irregular geometries.

Design/methodology/approach

In the present study, a three‐dimensional blocked‐off‐region procedure was presented and implemented in a numerical code based on the finite volume method to model combined conductive and radiative heat transfer in complex geometries. This formulation was developed and tested in three‐dimensional complex enclosures with diffuse reflective surfaces and containing gray absorbing‐emitting and isotropically scattering medium. This approach was applied to analyze the effect of the main of thermoradiative parameters on the temperature and flux values for three‐dimensional L‐shaped enclosure.

Findings

The proposed isotropic model leads to satisfactory solutions with comparison to reference data, which entitles us to extend it to anisotropic diffusion cases or to non‐gray media. The blocked‐off‐region procedure traits both straight and curvilinear boundaries. For curved or inclined boundaries, a fine or a non‐uniform grid is needed.

Originality/value

This paper offers a simple Cartesian practical technique to study the combined conductive and radiative heat transfer in three‐dimensional complex enclosures with both straight and curvilinear boundaries.
Effect of the local acceleration term on the MHD transient free convection flow over a vertical plate
Authors: Aldoss T.K. , Al‐Nimr M.A. , Khadrawi A.F.
Published: January 2007

Purpose

The transient hydrodynamics and thermal behavior of free convection flow over an isothermal vertical flat plate is investigated.

Design/methodology/approach

The study focuses on the role of the local acceleration term in the magnetohydrodynamic (MHD) momentum equation. A finite difference method based on a second‐order differential equation is used to solve the differential equations.

Findings

It is found that the local acceleration term has insignificant effect on the flow behavior especially at large values of magnetic forces. Also, it is found that the effect of the magnetic forces on the flow hydrodynamics behavior is significant but its effect on the thermal behavior is insignificant. It has been realized that the local acceleration term is usually small compared to the magnetic retarding force, and hence can be neglected.

Research limitations/implications

A quantitative description of the operating and geometrical parameters within which the local acceleration term may be significant is not available in the literature yet. Also, the authors' intention is to improve physical understanding of the hydrodynamic and thermal behaviors of the present problem.

Originality/value

The study provides results concerning the thermal behavior of free convection flow.
Fin placement for optimal forced convection heat transfer from a cylinder in cross‐flow
Authors: A/K Bassam , Abu‐Hijleh
Published: January 2007

Purpose

The aim of this work is to determine the optimal number and location of the fin(s) for maximum laminar forced convection heat transfer from a cylinder with multiple high conductivity radial fins on its outer surface in cross‐flow, i.e. Nusselt number, over a range of Reynolds numbers.

Design/methodology/approach

The effect of several combinations of number of fins, fin height, and fin(s) tangential location on the average Nusselt number was studied over the range of Reynolds numbers (5‐150). The problem was investigated numerically using finite difference method over a stretched grid. The optimal number and placement of the fins, for maximum Nusselt number, was determined for several combinations of Reynolds number and fin height. The percentage improvement in heat transfer per fin(s) unit length, i.e. cost‐efficiency, was also studied.

Findings

The results indicate that the fin(s) combination with the highest normalised Nusselt number is not necessarily the combination that results in the highest fin cost‐efficiency.

Originality/value

The results of the study can be used to design highly efficient cross‐flow forced convection heat transfer configurations from a horizontal cylinder with minimum cost.
A nonlinear numerical model for sloshing motion in tuned liquid dampers
Authors: Siddique M.R. , Hamed M.S. , El Damatty A.A.
Published: January 2007

Purpose

This paper presents a new numerical model that, unlike most existing ones, can solve the whole liquid sloshing, nonlinear, moving boundary problem with free surface undergoing small to very large deformations without imposing any linearization assumptions.

Design/methodology/approach

The time‐dependent, unknown, irregular physical domain is mapped onto a rectangular computational domain. The explicit form of the mapping function is unknown and is determined as part of the solution. Temporal discretization is based on one‐step implicit method. Second‐order, finite‐difference approximations are used for spatial discretizations.

Findings

The performance of the algorithm has been verified through convergence tests. Comparison between numerical and experimental results has indicated that the algorithm can accurately predict the sloshing motion of the liquid undergoing large interfacial deformations.

Originality/value

The ability to model liquid sloshing motion under conditions leading to large interfacial deformations utilizing the model presented in this paper improves our ability to understand the problem of sloshing motion in tuned liquid dampers (TLDs), which would eventually help in constructing more effective TLDs.
Process modeling of composites by resin transfer molding
Authors: Henz B.J. , Tamma K.K. , Mohan R.V. , Ngo N.D.
Published: January 2007

Purpose

The purpose of the present paper is to describe the modeling, analysis and simulations for the resin transfer molding (RTM), manufacturing process with particular emphasis on the sensitivity analysis for non‐isothermal applications.

Design/methodology/approach

For the manufacturing of advanced composites via RTM, besides the tracking of the resin flow fronts through a porous fiber perform, the heat transfer and the resin cure kinetics play an important role. The computational modeling is coupled multi‐disciplinary problem of flow‐thermal‐cure. The paper describes the so‐called continuous sensitivity formulation via the finite element method for this multi‐disciplinary problem for process modeling of composites manufactured by RTM to predict, analyze and optimize the manufacturing process.

Findings

Illustrative numerical examples are presented for two sample problems which include examination of sensitivity parameters for the case of material and geometric properties, and boundary conditions including fill time sensitivity analysis. The results indicate that the proposed formulations serve a useful role for the design and optimization of the RTM manufacturing process, thereby, avoiding heuristic trial‐and‐error methods.

Research limitations/implications

The paper restricts attention to constant properties and extensions to non‐linear thermophysical properties will serve as an added benefit.

Practical implications

The present efforts significantly impact the design/optimization process in the process modeling of composites manufactured by RTM.

Originality/value

To the authors' knowledge, this is the first time that continuous sensitivity analysis is done for non‐isothermal considerations in RTM.
Steady mixed convection flow of a micropolar fluid near the stagnation point on a vertical surface
Authors: Lok Y.Y. , Amin N. , Campean D. , Pop I.
Published: January 2007

Purpose

To study the steady mixed convection boundary‐layer flow of a micropolar fluid near the region of the stagnation point on a double‐infinite vertical flat plate is studied. The results of this paper are important for the researchers in the area of micropolar fluids.

Design/methodology/approach

For the case considered the problem reduces to a system of ordinary differential equations, which is solved numerically using the Keller‐box method. This method is very efficient for solving boundary‐layer problems and it can easily be applied to other general situations than that presented in this paper. Any PhD student can learn and apply it very easily.

Findings

Representative results for the velocity, microrotation and temperature profiles, as well as for the reduced skin friction coefficient and the local Nusselt number have been obtained for the case of strong concentration, Prandtl number of 0.7, some values of the material parameter K and the mixed convection parameter λ(≥0). Both assisting and opposing flow cases are considered. Results for the reduced skin friction coefficient and reduced local Nusselt number as well as for the reduced velocity, temperature and microrotation profiles are given in tables and figures. The obtained results are compared with ones from the open literature and it is found that they are in excellent agreement. The important conclusion is, we have been able to show that for opposing flow solutions are possible are possible only for a limited range of values of the mixed convection parameter λ.

Research limitations/implications

The results of this paper are valid only in the small region around the stagnation point on a vertical surface and they are not applicable outside this region.

Practical implications

The theory of micropolar fluids and also the results of the present paper can be used to explain the characteristics in certain fluids such as exotic lubricants, colloidal suspensions or polymeric fluids, liquid crystals, and animal blood.

Originality/value

The paper is very well prepared, presented and readable. We believe that the results are original and important from both theoretical and application point of views.
Stochastic perturbation‐based finite element approach to fluid flow problems
Authors: Kamiński Marcin , Carey Graham F.
Published: January 2007

Purpose

To generalize the traditional 2nd order stochastic perturbation technique for input random variables and fields and to demonstrate for flow problems.

Design/methodology/approach

The methodology is based on an n‐th order expansion (perturbation) for input random parameters and state functions around their expected value to recover probabilistic moments of the response. A finite element formulation permits stochastic simulations on irregular meshes for practical applications.

Findings

The methodology permits approximation of expected values and covariances of quantities such as the fluid pressure and flow velocity using both symbolic and discrete FEM computations. It is applied to inviscid irrotational flow, Poiseulle flow and viscous Couette flow with randomly perturbed boundary conditions, channel height and fluid viscosity to illustrate the scheme.

Research limitations/implications

The focus of the present work is on the basic concepts as a foundation for extension to engineering applications. The formulation for the viscous incompressible problem can be implemented by extending a 3D viscous primitive variable finite element code as outlined in the paper. For the case where the physical parameters are temperature dependent this will necessitate solution of highly non‐linear stochastic differential equations.

Practical implications

Techniques presented here provide an efficient approach for numerical analyses of heat transfer and fluid flow problems, where input design parameters and/or physical quantities may have small random fluctuations. Such an analysis provides a basis for stochastic computational reliability analysis.

Originality/value

The mathematical formulation and computational implementation of the generalized perturbation‐based stochastic finite element method (SFEM) is the main contribution of the paper.
Metal matrix composite processing: numerical study of heat transfer between fibers and metal
Authors: Cantarel Arthur , Lacoste Eric , Danis Michel , Arquis Eric
Published: January 2007

Purpose

To study heat transfer kinetics at the fiber scale in order to describe injection of liquid metal through a fibrous perform initially situated in a preheated mould, which is one of the various methods used in order to produce metal matrix composite materials (MMCs).

Design/methodology/approach

The first part presents a preliminary study in a static case to describe heat transfer kinetics between a fiber and the matrix in the case of a sudden contact of both components initially set up at different temperatures. This model enables to study the influence of the various parameters of the problem on heat transfer kinetics with phase change. In the second part, we present a modeling which takes into account the metal convection within the pores of the preform.

Findings

The numerical results of these two models justify the instantaneous thermal equilibrium assumption classically admitted to describe MMCs manufacturing methods. The results of this dynamic microscopic model are compared with the results issued from a single temperature macroscopic model to justify the methodological approach and the choice of the microscopic domain geometry representative of the MMCs manufacturing process.

Research limitations/implications

This first numerical model at the microscopic scale deals with the study of heat transfer between fibers and a pure metal. Next step will be the extension of this study to the preform infiltration by a metal alloy. Injection of matrix alloy implies the appearance of phenomena generated by segregation during phase changes.

Originality/value

The results of simulation tests, making use of the usual conditions of MMCs processing, show pretty good agreement with those of macroscopic models describing the anisothermal flow of a pure metal through a porous medium. From this coherence and from the results of the microscopic models as well, the hypothesis of instantaneous thermal equilibrium between fibers and metal (widely used in the literature to study the production of MMCs by infiltration of the liquid metal through the fibrous reinforcement) is justified. Moreover, it will be possible to extend it to the study of infiltration by an alloy, taking then into account thermal and solutal coupled transfers inside the study domain defined in the present work.
A hybrid differencing scheme for mass transport in electrochemical systems
Authors: Heppner Kevin L. , Evitts Richard W.
Published: January 2007

Purpose

To present a new hybrid differencing scheme for the numerical solution of an electromigration‐diffusion equation. The value of this work is evidenced by demonstrated improvement in the simulation of the Fu and Chan experiment when using the hybrid scheme.

Design/methodology/approach

A hybrid differencing scheme is developed which is based upon the solution of the pseudo‐steady state electromigration‐diffusion equation. In this scheme, a weighting parameter is calculated that varies the relative influence of the upwind node (relative to the direction of electromigration). This scheme significantly enhances the accuracy of electrochemical system mass transport models.

Findings

The hybrid scheme was compared to the upwind scheme. Use of the new hybrid scheme improved the accuracy of the model predictions by as much as 87 percent compared to the upwind scheme. However, use of the new scheme also increased the simulation time by between 6 and 43 percent. Deviations from electroneutrality and the presence of an activity coefficient gradient were detrimental to the stability of the hybrid scheme.

Research limitations/implications

This scheme is presented in the paper as an one‐dimensional (1D) scheme. However, it could be extended to more than 1D but some artificial viscosity may result.

Practical implications

The hybrid scheme developed and demonstrated herein is useful for researchers developing mass transport models of electrochemical systems. It has been proven capable of improving the accuracy of electrolyte mass transport models.

Originality/value

This is the first hybrid differencing scheme designed for the special characteristics of electrochemical mass transport systems. It greatly improves the accuracy of simulation results. This work is useful to those who mathematically model electrochemical systems.
A two‐dimensional numerical procedure for a three dimensional internal flow through a complex passage with a small depth (its application to numerical analysis of fluidic oscillators)
Authors: Nakayama A. , Kuwahara F. , Kamiya Y.
Published: January 2007

Purpose

To introduce an efficient two‐dimensional numerical procedure for a three‐dimensional internal flow through a complex passage with a small depth, in which the viscous effects from upper and lower walls are significant.

Design/methodology/approach

A set of two‐dimensional governing equations has been derived by integrating the full three‐dimensional Navier‐Stokes equations over the depth. Then, this set of the governing equations has been discretized using a finite volume method. Simple algorithm and quick scheme are used to solve the resulting discretized equations.

Findings

A numerical experiment conducted to investigate the oscillation mechanism of a feedback fluidic oscillator reveals that the feedback passage plays an important role of transmitting the pressure rise to the control port, which triggers the jet stream to deflect towards the opposite side wall in the reaction region. Comparison of the prediction and experiment substantiates the validity of the present numerical procedure.

Originality/value

The two‐dimensional numerical procedure, proposed in this study, will be used by researchers and practitioners to investigate various kinds of complex passages with a small depth. Especially, those who are interested in fluidic devices may find it extremely convenient to conduct numerical experiments.
Three‐dimensional numerical simulation of g‐jitter induced convection and solute transport in magnetic fields
Authors: Li K. , Li B.Q. , Handa J. , de Groh H.C.
Published: January 2007

Purpose

The quality of crystals grown in space can be diversely affected by the melt flows induced by g‐jitter associated with a space vehicle. This paper presents a full three‐dimensional (3D) transient finite element analysis of the complex fluid flow and heat and mass transfer phenomena in a simplified Bridgman crystal growth configuration under the influence of g‐jitter perturbations and magnetic fields.

Design/methodology/approach

The model development is based on the Galerkin finite element solution of the magnetohydrodynamic governing equations describing the thermal convection and heat and mass transfer in the melt. A physics‐based re‐numbering algorithm is used to make the formidable 3D simulations computationally feasible. Simulations are made using steady microgravity, synthetic and real g‐jitter data taken during a space flight.

Findings

Numerical results show that g‐jitter drives a complex, 3D, time dependent thermal convection and that velocity spikes in response to real g‐jitter disturbances in space flights, resulting in irregular solute concentration distributions. An applied magnetic field provides an effective means to suppress the deleterious convection effects caused by g‐jitter. Based on the simulations with applied magnetic fields of various strengths and orientations, the magnetic field aligned with the thermal gradient provides an optimal damping effect, and the stronger magnetic field is more effective in suppressing the g‐jitter induced convection. While the convective flows and solute transport are complex and truly 3D, those in the symmetry plane parallel to the direction of g‐jitter are essentially two‐dimensional (2D), which may be approximated well by the widely used 2D models.

Originality/value

The physics‐based re‐numbering algorithm has made possible the large scale finite element computations for 3D g‐jitter flows in a magnetic field. The results indicate that an applied magnetic field can be effective in suppressing the g‐jitter driven flows and thus enhance the quality of crystals grown in space.
Quadratic Petrov‐Galerkin finite elements for advective‐reactive features in turbomachinery CFD
Authors: Corsini Alessandro , Rispoli Franco , Santoriello Andrea
Published: January 2007

Purpose

An original finite element scheme for advection‐diffusion‐reaction problems is presented. The new method, called spotted Petrov‐Galerkin (SPG), is a quadratic Petrov‐Galerkin (PG) formulation developed for the solution of equations where either reaction (associated to zero‐order derivatives of the unknown) and/or advection (proportional to first‐order derivatives) dominates on diffusion (associated to second‐order derivatives). The addressed issues are turbulence and advective‐reactive features in modelling turbomachinery flows.

Design/methodology/approach

The present work addresses the definition of a new PG stabilization scheme for the reactive flow limit, formulated on a quadratic finite element space of approximation. We advocate the use of a higher order stabilized formulation that guarantees the best compromise between solution stability and accuracy. The formulation is first presented for linear scalar one‐dimensional advective‐diffusive‐reactive problems and then extended to quadrangular Q2 elements.

Findings

The proposed advective‐diffusive‐reactive PG formulation improves the solution accuracy with respect to a standard streamline driven stabilization schemes, e.g. the streamline upwind or Galerkin, in that it properly accounts for the boundary layer region flow phenomena in presence of non‐equilibrium effects.

Research limitations/implications

The numerical method here proposed has been designed for second‐order quadrangular finite‐elements. In particular, the Reynolds‐Averaged Navier‐Stokes equations with a non‐linear turbulence closure have been modelled using the stable mixed element pair Q2‐Q1.

Originality/value

This paper investigated the predicting capabilities of a finite element method stabilized formulation developed for the purpose of solving advection‐reaction‐diffusion problems. The new method, called SPG, demonstrates its suitability in solving the typical equations of turbulence eddy viscosity models.
Numerical study of forced convection in a 3D flow of a non‐Newtonian fluid through a porous duct
Authors: Nebbali R. , Bouhadef K.
Published: January 2007

Purpose

To investigate the forced convection heat transfer to hydrodynamically and thermally fully developed laminar steady flow of power‐law non‐Newtonian fluid in a partially porous square duct.

Design/methodology/approach

The modified Brinkmann‐Forchheimer extended Darcy model for power‐law fluids is used in the porous layer. The solutions for the velocity and temperature fields are obtained numerically using the finite volume method. Computations are performed over a range of Darcy number, power‐law indices, porous insert thickness and thermal conductivity ratio.

Findings

The average Nusselt number and the Fanning factor, so obtained are found to be in good agreement with the literature. It is highlighted that a heat transfer improvement is obtained when the channel is entirely porous and this enhancement is maximized at low permeability. While depending on the working conditions, heat transfer enhancement can also be obtained by filling partially the duct with the porous insert, even if the conductivity ratio is equal to 1. The results indicate also that the conductivity ratio has a strong impact on the heat transfer enhancement at high permeability, while this impact is significant beyond a critical thickness of the porous layer at low permeability. It is found that both shear‐thinning (n<1) and shear‐thickening (n>1) fluids allow obtaining the highest Nusselt number according to the properties of the porous insert. The presence of the porous insert causes a significant increase in pressure drop. This added pressure drop is found to be more important with shear thickening fluids (n>1).

Research limitations/implications

The results of this paper are valid for square ducts and H1 thermal boundary condition, corresponding to an axially uniform heat flux and peripherally uniform temperature. The inertial effects are neglected in the porous region.

Practical implications

The obtained results can be used in the design of heat exchangers and in the cooling of electronic equipments.

Originality/value

This work investigates some interesting ways to enhance heat transfer in three‐dimensional square ducts by using porous substrates and non‐Newtonian fluids. It is believed that the case studied in this paper has not previously been investigated.
Fin angle effect on turbulent heat transfer in parallel‐plate channel with flow‐inclining fins
Authors: Yuan Z.X. , Zhao L.H. , Zhang B.D.
Published: January 2007

Purpose

This paper aims to develop enhanced surfaces that possess improved heat transfer rate with moderate flow pressure‐drop.

Design/methodology/approach

The characteristics of the heat transfer and flow resistance in a parallel‐plate channel with flow‐inclining fins have been numerically and experimentally studied. In the turbulent flow range, the effect of the fin angle from 0 to 23.2° in addition to three channel heights, has been investigated.

Findings

The friction factor and the Nusselt number of the experimented 3D finned ducts are both lower than those of the numerical 2D channel at the same Reynolds number. The assessment under the constraint of the same pump power consumption shows that the enhancement ratio, Num/Nu0, is in between 1.6 ∼ 3.3. Showing different priority, the fin of β=23.2° is the most profitable for the 2D channel, while the case of β=16.0° is superior to the other fin angles for thicker 3D ducts.

Research limitations/implications

For wide flat channels the 3D fins rather than the 2D fins are profitable. The deployment of the 3D fin, which is unchangeable in the current study, should be further optimized. The fin dimension and configuration in other duct forms are also challenging subjects.

Practical implications

The results can be referenced by those who engage in design of plate‐fin heat exchangers. Attention should be paid to the optimum fin angle for different aspect ratios of the duct.

Originality/value

The study provides a practical fulfillment of the effective enhancement of the convective heat transfer with properly designed inserts that the field synergy principle predicted.
Response surface‐based shape optimization of a Francis draft tube
Authors: Marjavaara Daniel , Lundström Staffan
Published: January 2007

Purpose

This paper aims to develop an efficient and accurate numerical method that can be used in the design process of the waterways in a hydropower plant.

Design/methodology/approach

A range of recently published (2002‐2006) works, which aim to form the basis of a shape optimization tool for flow design and to increase the knowledge within the field of computational fluid dynamics (CFD) and surrogate‐based optimization techniques.

Findings

Provides information about how crude the optimization method can be regarding, for example, the design variables, the numerical noise and the multi objectives, etc.

Research limitations/implications

It does not give a detailed interpretation of the flow behaviour due to the lack of validation data.

Practical implications

A very useful flow design methodology that can be used in both academy and industry.

Originality/value

Shape optimization of hydraulic turbine draft tubes with aid of CFD and numerical optimization techniques has not been performed until recently due to the high CPU requirements on CFD simulations. The paper investigates the possibilities of using the global optimization algorithm response surface methodology in the design process of a full scale hydraulic turbine draft tube.