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1 – 10 of 33L. Škerget, M. Hriberšek and Z. Žunič
A numerical method for the solution of the Navier‐Stokes equations is developed using an integral representation of the conservation equations. The velocity‐vorticity formulation…
Abstract
A numerical method for the solution of the Navier‐Stokes equations is developed using an integral representation of the conservation equations. The velocity‐vorticity formulation is employed, where the kinematics is given with the Poisson equation for a velocity vector, while the kinetics is represented with the vorticity transport equation. The corresponding boundary‐domain integral equations are presented along with discussions of the kinetics and kinematics of the fluid flow problem. The boundary‐domain integral formulation is developed and tested for natural convection flows in closed cavities with complex geometries.
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This paper aims to examine the impact of bank liquidity, monetary policy and global crises on bank risk-taking behavior of Vietnamese banks. It provides evidence for a risk-taking…
Abstract
Purpose
This paper aims to examine the impact of bank liquidity, monetary policy and global crises on bank risk-taking behavior of Vietnamese banks. It provides evidence for a risk-taking channel of monetary policy through bank liquidity and global crises.
Design/methodology/approach
The study uses the data set of 572 observations from 35 banks operating in Vietnam between 2005 and 2022, using the GMM regression technique.
Findings
The findings indicate that banks with higher liquidity tend to take more risks in the long run. Additionally, expansionary monetary policies encourage banks to take on more risk. Bank liquidity and global crises, such as the global financial crisis and the COVID-19 pandemic, not only directly affect bank risk-taking but also indirectly through monetary policy.
Originality/value
This paper expands the existing literature by examining the effect of bank liquidity, monetary policy and global crises on bank risk-taking by using the GMM and two models of which the authors regress the impact with and without bank liquidity and global crises. New factors affecting risk-taking, including operating cost, financial crisis and the COVID-19 pandemic are added into the model.
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This paper gives a bibliographical review of the finite element and boundary element parallel processing techniques from the theoretical and application points of view. Topics…
Abstract
This paper gives a bibliographical review of the finite element and boundary element parallel processing techniques from the theoretical and application points of view. Topics include: theory – domain decomposition/partitioning, load balancing, parallel solvers/algorithms, parallel mesh generation, adaptive methods, and visualization/graphics; applications – structural mechanics problems, dynamic problems, material/geometrical non‐linear problems, contact problems, fracture mechanics, field problems, coupled problems, sensitivity and optimization, and other problems; hardware and software environments – hardware environments, programming techniques, and software development and presentations. The bibliography at the end of this paper contains 850 references to papers, conference proceedings and theses/dissertations dealing with presented subjects that were published between 1996 and 2002.
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E.J. Sellountos, Jorge Tiago and Adelia Sequeira
This paper aims to describe the 2D meshless local boundary integral equation (LBIE) method for solving the Navier–Stokes equations.
Abstract
Purpose
This paper aims to describe the 2D meshless local boundary integral equation (LBIE) method for solving the Navier–Stokes equations.
Design/methodology/approach
The velocity–vorticity formulation is selected to eliminate the pressure gradient of the equations. The local integral representations of flow kinematics and transport kinetics are derived. The integral equations are discretized using the local RBF interpolation of velocities and vorticities, while the unknown fluxes are kept as independent variables. The resulting volume integrals are computed using the general radial transformation algorithm.
Findings
The efficiency and accuracy of the method are illustrated with several examples chosen from reference problems in computational fluid dynamics.
Originality/value
The meshless LBIE method is applied to the 2D Navier–Stokes equations. No derivatives of interpolation functions are used in the formulation, rendering the present method a robust numerical scheme for the solution of fluid flow problems.
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Konstantinos Stokos, Socrates Vrahliotis, Theodora Pappou and Sokrates Tsangaris
– The purpose of this paper is to present a numerical method for the simulation of steady and unsteady incompressible laminar flows, including convective heat transfer.
Abstract
Purpose
The purpose of this paper is to present a numerical method for the simulation of steady and unsteady incompressible laminar flows, including convective heat transfer.
Design/methodology/approach
A node centered, finite volume discretization technique is applied on hybrid meshes. The developed solver, is based on the artificial compressibility approach.
Findings
A sufficient number of representative test cases have been examined for the validation of this numerical solver. A wide range of the various dimensionless parameters were applied for different working fluids, in order to estimate the general applicability of our solver. The obtained results agree well with those published by other researchers. The strongly coupled solution of the governing equations showed superiority compared to the loosely coupled solution as inviscid effects increase.
Practical implications
Convective heat transfer is dominant in a wide variety of practical engineering problems, such as cooling of electronic chips, design of heat exchangers and fire simulation and suspension in tunnels.
Originality/value
A comparison between the strongly coupled solution and the loosely coupled solution of the Navier-Stokes and energy equations is presented. A robust upwind scheme based on Roe’s approximate Riemann solver is proposed.
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Chunyang Wang, Moghtada Mobedi and Fujio Kuwahara
The purpose of this study is to validate whether the local thermal equilibrium for unsteady state is an appropriate assumption for the porous media with closed pores. It also…
Abstract
Purpose
The purpose of this study is to validate whether the local thermal equilibrium for unsteady state is an appropriate assumption for the porous media with closed pores. It also compares the transient temperatures between the pore scale and volume averaged approaches to prove that the volume averaged method is an appropriate technique for the heat transfer in closed-cell porous media. The interfacial heat transfer coefficient for the closed-cell porous media is also discussed in details.
Design/methodology/approach
The governing equations for the pore scale and continuum domains are given. They are solved numerically for the pore scale and volume-averaged domains. The results are compared and discussion was done. The performed discussions and explanations are supported with figure and graphics.
Findings
A local thermal non-equilibrium exits for the closed-cell porous media in which voids are filled with water during the unsteady heat transfer process. Local thermal non-equilibrium condition exists in the cells under high temperature gradient and it disappears when the heat transfer process becomes steady-state. Although a local thermal equilibrium exists in the porous media in which the voids are filled with air, a finite value for heat transfer coefficient is found. The thermal diffusivity of air and solid phase are close to each other and hence a local thermal equilibrium exists.
Research limitations/implications
The study is done only for the closed-cell porous media and for Rayleigh number till 105. Two common working fluids as water and air are considered.
Practical implications
There are many applications of porous media with closed pores particularly in the industry, such as the closed-cell metal foam or the closed cells in porous materials such as foods and plastic-based insulation material. The obtained results are important for transient heat transfer in closed-cell porous materials.
Social implications
The obtained results are important from the transient application of heat transfer in the closed-cell material existing in nature and industry.
Originality/value
The authors’ literature survey shows that it is the first time the closed-cell porous media is discussed from local thermal non-equilibrium point of view and it is proved that the local thermal non-equilibrium can exist in the closed-cell porous media. Hence, two equations as solid and fluid equations should be used for unsteady heat transfer in a closed-cell porous medium.
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Simona Jevšnik, Jelka Geršak and Ivan Gubenšek
The purpose of this paper is to analyse some mechanical properties and parameters of drapability using different methods from two different points of research area: knowledge…
Abstract
Purpose
The purpose of this paper is to analyse some mechanical properties and parameters of drapability using different methods from two different points of research area: knowledge bases and numerical modelling using the finite element method.
Design/methodology/approach
The approach consists of analysing some mechanical properties and parameters of drapability using different methods from two different points of research area: knowledge bases and numerical modelling using the finite element method. The knowledge bases, named FP_B‐1 and FPO_B‐2, were used to analyse the bending rigidity of fused panels. The numerical model of fused panel NMFP is used to analyse parameters of drapability.
Findings
Based on the analyses of bending rigidity and draping of fused panels the conclusions indicate the significance of interaction between mechanical properties and parameters of drapability of the fused panel to garment appearance. Furthermore, the methods used present a computer approach to the study of the fused panel properties important for the computer‐based engineering and the presentation of real behaviour of all aspects of clothes.
Practical implications
This numerical model of a fused panel enables a 3D observation of this aspect of clothes' which is a behaviour, very important contribution to the computer planning of the behaviour of produced clothes.
Originality/value
A better understanding of how to construct fused panels in clothing.
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Presents the influence of seam length, normal stitching velocity of a sewing machine and a working method on stitching velocity of sewing. Results show that better stitching…
Abstract
Presents the influence of seam length, normal stitching velocity of a sewing machine and a working method on stitching velocity of sewing. Results show that better stitching velocities of sewing are gained by longer length of seams and higher than normal stitching velocities of a sewing machine. Reveals the working method and type of feeding of material affect the achievement of higher stitching velocities.
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Discusses the 6th ITCRR, its breadth of textile and clothing research activity, plus the encouragement given to workers in this field and its related areas. States that, within…
Abstract
Discusses the 6th ITCRR, its breadth of textile and clothing research activity, plus the encouragement given to workers in this field and its related areas. States that, within the newer research areas under the microscope of the community involved, technical textiles focuses on new, ‘smart’ garments and the initiatives in this field in both the UK and the international community at large. Covers this subject at length.
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Mu‐Huan Chiang and Gregory T. Byrd
Data‐centric storage is an efficient scheme to store and retrieve event data in sensor networks, but with the multi‐hop routing nature of sensor networks, the communication cost…
Abstract
Data‐centric storage is an efficient scheme to store and retrieve event data in sensor networks, but with the multi‐hop routing nature of sensor networks, the communication cost of the home nodes and their neighboring nodes tends to be much higher than the other nodes. These hot‐spots can adversely impact system lifetime by draining off their limited energy rapidly. In this paper, we present Zone‐Repartitioning, a load‐balancing mechanism that reduces the energy consumption of the hot‐spots by distributing their communication load while event frequency is high. The trade‐off between event storage cost and query cost makes Zone Repartitioning a competitive approach in different kinds of applications. We compare the performance of Zone Repartitioning against GHT and show that Zone Repartitioning provides better adaptability in various sensor network scenarios.
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