摘要:

AbstractThe performances of various numerical schemes used to model hyperbolic/parabolic equations have been studied by the calculation of their numerical group velocities. Numerical experiments conducted with one dimensional linear and quadratic Lagrangian finite elements with a Crank‐Nicolson finite differencing in time confirm the results of the analysis. The group velocity analysis supplements the well‐known amplitude and phase portraits introduced by Leendertse1and helps explain the occurrence and behaviour of numerical oscillations in both finite difference and finite element sche

ISSN:0271-2091    

DOI:10.1002/fld.1650050302

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA comparative study of seven discretization schemes for the equations describing convection‐diffusion transport phenomena is presented. The (differencing) schemes considered are the conventional central‐ and upwind‐difference schemes, together with the Leonard,1Leonard upwind1and Leonard super upwind difference1schemes. Also tested are the so called locally exact difference scheme2and the quadratic‐upstream difference scheme.3,4In multidimensional problems errors arise from ‘false‐diffusion’ and function approximations. It is asserted that false diffusion is essentially a multidimensional source of error. No mesh constraints are associated with errors in function approximation and discretization. Hence errors associated with discretization only may be investigated via one‐dimensional problems. Thus, although the above schemes have been tested for one‐ and two‐dimensional flows with sources, only the former are presented here. For 1D flows, the Leonard super upwind difference scheme and the locally exact scheme are shown to be far superior in accuracy to the others at all Peclet numbers and for most source distributions, for the test cases considered. Furthermore, the latter is shown to be considerably cheaper in computational terms than the former. The stability of the schemes and their CPU time requirements

ISSN:0271-2091    

DOI:10.1002/fld.1650050303

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe procedure proposed is based on the solution by finite difference means of a set of Laplace's equations, by the application of a relaxation method.The curvilinear orthogonal grid so generated is fitted to a 2‐D physical domain with closed boundary and the contribution of the present work consists in the arbitrary choice of grid points on two adjacent boundaries, in order to achieve the desired density of grid points where the geometry of the boundaries varies rapidly.The method proposed is rapid and stable. Some characteristic examples are finally presente

ISSN:0271-2091    

DOI:10.1002/fld.1650050304

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractAn application of the depth‐integratedk‐ϵ turbulence model is presented for separated flow in a wide, shallow, rectangular channel with an abrupt expansion in width. The well‐known numerical problems associated with the use of upwind and central finite differences for convection are overcome by the adoption of the spatially third‐order accurate QUICK finite difference technique. Results show that modification of the depth‐integratedk‐ϵ turbulence closure model for streamline curvature leads to significant improvement in the agreement between model predictions and experimental

ISSN:0271-2091    

DOI:10.1002/fld.1650050305

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractIn this paper the integrated solution approach, the penalty function approach and the solenoidal approach for the finite element solution of the stationary Navier‐Stokes equations are compared. It is shown that both the penalty function approach and the solenoidal approach compare favourably to the integrated solution method. For fine meshes the solenoidal approach appears to be the cheapest metho

ISSN:0271-2091    

DOI:10.1002/fld.1650050306

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractIn this paper a fully explicit finite element method (FEFEM) is presented for solving steady incompressible viscous flow problems. This full explicitness is achieved by combining the multiplier (or augmented Lagrangian) method with a pseudo‐time‐iteration method. FEFEM needs no global matrix at all and is of great advantage to large‐scale problems because they can be solved within the limit of core memory.The optimum choice of a time increment and a penalty parameter is discussed and the driven cavity flow at a Reynolds number of 1000 is computed with a refined mesh (60 × 60 ele

ISSN:0271-2091    

DOI:10.1002/fld.1650050307

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650050308

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractWe summarize here some theoretical results for fictitious gas regularization of compressible flow and give error estimates for the finite element approximation to the regularized problem.

ISSN:0271-2091    

DOI:10.1002/fld.1650050309

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650050310

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650050311

出版商:John Wiley&Sons, Ltd    

年代:1985

数据来源: WILEY