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Article
Publication date: 1 September 2005

J.G. Wang, L. Yan and G.R. Liu

Develop a local radial point interpolation method (LRPIM) to analyze the dissipation process of excess pore water pressure in porous media and verify its numerical capability.

Abstract

Purpose

Develop a local radial point interpolation method (LRPIM) to analyze the dissipation process of excess pore water pressure in porous media and verify its numerical capability.

Design/methodology/approach

Terzaghi's consolidation theory is used to describe the dissipation process. A local residual form is formulated over only a sub‐domain. This form is spatially discretized by radial point interpolation method (RPIM) with basis of multiquadrics (MQ) and thin‐plate spline (TPS), and temporally discretized by finite difference method. One‐dimensional (1D) and two‐dimensional consolidation problems are numerically analyzed.

Findings

The LRPIM is suitable, efficient and accurate to simulate this dissipation process. The shape parameters, q=1.03, R=0.1 for MQ and η=4.001 for TPS, are still valid.

Research limitations/implications

The asymmetric system matrix in LRPIM spends more resources in storage and CPU time.

Practical implications

Local residual form requires no background mesh, thus being a truly meshless method. This provides a fast and practical algorithm for engineering computation.

Originality/value

This paper provides a simple, accurate and fast numerical algorithm for the dissipation process of excess pore water pressure, largely simplifies data preparation, shows that the shape parameters from solid mechanics are also suitable for the dissipation process.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 15 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 March 1993

J. PETERA, V. NASSEHI and J.F.T. PITTMAN

A number of finite element formulations involving discontinuous weighting functions have been tested against analytic solutions for a steady scalar convection—diffusion problem at…

Abstract

A number of finite element formulations involving discontinuous weighting functions have been tested against analytic solutions for a steady scalar convection—diffusion problem at intermediate Peclet number, with a ‘hard’ downstream boundary condition. The emphasis is on extending these methods to isoparametric bilinear and biquadratic elements. In order to do this a procedure is given for the exact calculation of shape function Laplacians. Having confirmed the success of the Brooks—Hughes streamline upwind Petrov—Galerkin (SUPG) method for isoparametric bilinear elements, formulations for biquadratic elements are examined. Galerkin least squares offers little advantage over SUPG in the test problem. The generalized Galerkin method of Donea et al. gave excellent results, but because of concern over the possibility of cross‐streamline artificial diffusion in some cases, a strictly streamline formulation incorporating the optimal parameters of Donea et al. is proposed. This gave excellent results on a sufficiently refined mesh.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 3 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 December 2005

Alessandro Corsini, Franco Rispoli and Andrea Santoriello

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…

Abstract

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.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 15 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 June 1994

Marcela B. Goldschmit and Eduardo N. Dvorkin

A generalized Galerkin technique originally developed by Donea,Belytschko and Smolinski for solving the steady convection—diffusionequation using elements with quadratic…

Abstract

A generalized Galerkin technique originally developed by Donea, Belytschko and Smolinski for solving the steady convection—diffusion equation using elements with quadratic interpolation has been modified to extend its application to the case of geometrically distorted 1D and 2D elements. The numerical results indicate that the modified scheme gives accurate results and presents a rather small sensitivity to element distortions.

Details

Engineering Computations, vol. 11 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 2 March 2015

Rosilene A. Kraft and Alvaro L. G. A. Coutinho

The purpose of this paper is to show benefits of deflated preconditioned conjugate gradients (CG) in the solution of transient, incompressible, viscous flows coupled with heat…

Abstract

Purpose

The purpose of this paper is to show benefits of deflated preconditioned conjugate gradients (CG) in the solution of transient, incompressible, viscous flows coupled with heat transfer.

Design/methodology/approach

This paper presents the implementation of deflated preconditioned CG as the iterative driver for the system of linearized equations for viscous, incompressible flows and heat transfer simulations. The De Sampaio-Coutinho particular form of the Petrov-Galerkin Generalized Least Squares finite element formulation is used in the discretization of the governing equations, leading to symmetric positive definite matrices, allowing the use of the CG solver.

Findings

The use of deflation techniques improves the spectral condition number. The authors show in a number of problems of coupled viscous flow and heat transfer that convergence is achieved with a lower number of iterations and smaller time.

Originality/value

This work addressed for the first time the use of deflated CG for the solution of transient analysis of free/forced convection in viscous flows coupled with heat transfer.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 25 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 5 July 2021

Abhishek Kumar Singh and Krishna Mohan Singh

The work presents a novel implementation of the generalized minimum residual (GMRES) solver in conjunction with the interpolating meshless local Petrov–Galerkin (MLPG) method to…

Abstract

Purpose

The work presents a novel implementation of the generalized minimum residual (GMRES) solver in conjunction with the interpolating meshless local Petrov–Galerkin (MLPG) method to solve steady-state heat conduction in 2-D as well as in 3-D domains.

Design/methodology/approach

The restarted version of the GMRES solver (with and without preconditioner) is applied to solve an asymmetric system of equations, arising due to the interpolating MLPG formulation. Its performance is compared with the biconjugate gradient stabilized (BiCGSTAB) solver on the basis of computation time and convergence behaviour. Jacobi and successive over-relaxation (SOR) methods are used as the preconditioners in both the solvers.

Findings

The results show that the GMRES solver outperforms the BiCGSTAB solver in terms of smoothness of convergence behaviour, while performs slightly better than the BiCGSTAB method in terms of Central processing Unit (CPU) time.

Originality/value

MLPG formulation leads to a non-symmetric system of algebraic equations. Iterative methods such as GMRES and BiCGSTAB methods are required for its solution for large-scale problems. This work presents the use of GMRES solver with the MLPG method for the very first time.

Details

Engineering Computations, vol. 39 no. 2
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 8 May 2018

Pedro Areias, Jebun Naher Sikta and Manuel Pereira dos Santos

The purpose of this paper is to provide an analysis of dust acoustic (solitary) waves including viscosity. Specifically, the authors consider a dusty unmagnetized plasma system…

Abstract

Purpose

The purpose of this paper is to provide an analysis of dust acoustic (solitary) waves including viscosity. Specifically, the authors consider a dusty unmagnetized plasma system consisting of negatively charged dust and Boltzmann electrons and ions.

Design/methodology/approach

In this paper, a Petrov–Galerkin weak form with upwinding is adopted. Nonlinearity of ion and electron number density in terms of an electrostatic potential is included. A fully implicit time integration is used (backward Euler method), which requires the first derivative of the weak form. A three-field formulation is proposed, with the dust number density, the electrostatic potential and the dust velocity being the unknown fields.

Findings

In this study, two numerical examples are introduced and results show great promise for the proposed formulation as a predictive tool in viscous dusty plasmas. Presence of solitary waves was demonstrated. Dusty plasma vortices are predicted in 2D and 3D, as mentioned in the specialized literature.

Research limitations/implications

We observed some dependence on step size, which is due to the simple time-stepping scheme. This can be solved with a higher order integration scheme, which implies an added cost to the solution.

Practical implications

Dusty plasmas are found in astrophysics (Saturn rings) and electronics industry at several scales and have high impact as a contaminant.

Originality/value

To the authors’ knowledge, this is the first paper with a simulation of dusty plasma including vortices.

Details

Engineering Computations, vol. 35 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 April 1989

G.F. CAREY and M. SHARMA

A flux‐upwind finite element method is developed for the carrier transport equations in semiconductor device modeling. Our approach is motivated by the streamline upwind methods…

Abstract

A flux‐upwind finite element method is developed for the carrier transport equations in semiconductor device modeling. Our approach is motivated by the streamline upwind methods that have proven effective in fluid mechanics. The procedure reduces precisely to the Scharfetter‐Gummel approach in one dimension. In higher‐dimensions, however, it differs from this classical technique and is shown here to generate more accurate solutions with less numerical dissipation. Numerical results are presented for representative MOSFET and pn junction devices to illustrate this point. Both upwind techniques have been implemented in conjunction with an adaptive finite element refinement procedure for better layer resolution and yield a more stable algorithm.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 8 no. 4
Type: Research Article
ISSN: 0332-1649

Article
Publication date: 1 February 1992

D. LEFEBVRE, J. PERAIRE and K. MORGAN

We investigate the application of a least squares finite element method for the solution of fluid flow problems. The least squares finite element method is based on the…

Abstract

We investigate the application of a least squares finite element method for the solution of fluid flow problems. The least squares finite element method is based on the minimization of the L2 norm of the equation residuals. Upon discretization, the formulation results in a symmetric, positive definite matrix system which enables efficient iterative solvers to be used. The other motivations behind the development of least squares finite element methods are the applicability of higher order elements and the possibility of using the norm associated to the least squares functional for error estimation. For steady incompressible flows, we develop a method employing linear and quadratic triangular elements and compare their respective accuracy. For steady compressible flows, an implicit conservative least squares scheme which can capture shocks without the addition of artificial viscosity is proposed. A refinement strategy based upon the use of the least squares residuals is developed and several numerical examples are used to illustrate the capabilities of the method when implemented on unstructured triangular meshes.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 2 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 January 1994

J. Lim, C.L. Chan and A. Chandra

A boundary element method (BEM) formulation for the solutionof transient conduction‐convection problems is developed in thispaper. A time‐dependent fundamental solution for moving…

Abstract

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.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 4 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

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