摘要:

AbstractA computational procedure for compressible axisymmetric boundary layers, on bodies of revolution, in transition from laminar to turbulent flow, is introduced. The procedure is an extension of a former method, due to Patankar and Spalding.The flow field is computed by solution of four simultaneous equations for the momentum, the thermal energy, the turbulence energy amplitude and the turbulent scale.The results show good agreement with existing theoretical and experimental data.

ISSN:0271-2091    

DOI:10.1002/fld.1650020102

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe frequently used reduced integration method for solving incompressible flow problems ‘a la penalty’ is critically examined vis‐a‐vis the consistent penalty method. For the limited number of quadrilateral and hexahedral elements studied, it is shown that the former method is only equivalent to the latter in certain special cases. In the general case, the consistent penalty method is shown to be more accurate. Finally, we demonstrate significant advantages of a new element, employing biquadratic (2‐D) or triquadratic (3‐D) velocity andlinearpressure over that using the same velocity but employing bilinear (2‐D) or trilinear (3‐D) pressur

ISSN:0271-2091    

DOI:10.1002/fld.1650020103

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThis paper considers the multigrid iterative method applied to the solution of finite difference approximations to a linear second‐order self‐adjoint elliptic equation. It represents an extension of work by Dinar and Brandt. We compare two methods to obtain fourth‐order convergence. The first is local error extrapolation developed by Brandt, the second is iterative improvement developed by Lindberg. This work considers non‐separable problems, but only on a rectangular domain with Dirichlet boundary conditions. We consider test cases with non‐smooth (i.e. discontinuous second derivatives) as well as smooth solutions. We also apply the multigrid method to an elliptic equation with non‐separable coefficients which occurs in a geothermal model. In this case an analysis of the error fails to show any advantage in a fourth‐order difference scheme over a second‐order scheme. However, we do demonstrate that the multigrid iteration performs well on this problem. Also, this example shows that the multigrid iteration can be combined with iterative improvement to create an efficient fourth‐order method for a non‐separable elliptic equation which is coupled with a marching equation. Other work has found an advantage in this fourth‐order scheme for a sim

ISSN:0271-2091    

DOI:10.1002/fld.1650020104

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractFinite‐difference and finite‐element techniques have been used to calculate the steady laminar flow over a flat plate normal to an air stream, up to a Reynolds number, Re, based on the plate half‐width, of 100. The boundary conditions simulate a central splitter plate downstream of the body, to prevent vortex shedding, so the flow is characterized by a closed recirculation region which grows with increasing Re but at Re =O(100) is very similar in size to the turbulent recirculating region that occurs in the corresponding high Reynolds‐number flow. Motivation came, in part, from the increasing efforts of turbulence modellers to calculate complex turbulent flows (containing elliptic regions) and our belief that the numerical methods commonly employed for such work can be inaccurate. The predictions are compared with each other and with some expectations based on classic solutions of the Navier‐Stokes equations, and the nature of the numerical errors is demonstrated. It is concluded that effort comparable with that expended in developing turbulence models should be directed to developing higher‐order numerical methods, before the numerical accuracy of predictions of, for example, bluff‐body flows can be made sufficiently high to sustain detailed discussion of the adequacy of turbulence models in su

ISSN:0271-2091    

DOI:10.1002/fld.1650020105

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA finite element method for solving shallow water flow problems is presented. The standard Galerkin method is employed for spatial discretization. The numerical integration scheme for the time variation is the explicit two step scheme, which was originated by the authors and their co‐workers. However, the original scheme has been improved to remove the erroneous artifical damping effect. Since the improved scheme employs a combination of lumped and unlumped coefficients, the scheme is referred to as a selective lumping scheme. Stability conditions and accuracy are investigated by considering several numerical examples. The method has been applied to the tidal flow in Osaka Bay and Yatsushiro Ba

ISSN:0271-2091    

DOI:10.1002/fld.1650020106

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650020107

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650020101

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY