摘要:

AbstractBased on a two‐dimensional potential flow theory, earthquake‐induced hydrodynamic pressures on a rigid dam with a non‐vertical upstream face are examined by the Trefftz method. The effect of surface waves on the hydrodynamic pressure distribution is discussed in detail. Numerical values are given for different wave effect parameters and different geometries of the dam–water in

ISSN:0271-2091    

DOI:10.1002/fld.1650090102

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractHarten's second‐order‐accurate total‐variation‐diminishing (TVD) scheme is applied to calculation of flow from the open end of a shock tube. Comparison of numerical results with available experimental data for overpressure at selected points around the shock tube exit shows good agreement. Numerically indicated positions of the moving shock front and Mach stem also compare well with flow shadowgraph data. Where the problem geometry is sufficiently simple and rectangular gridding can be used, Harten's method affords a good choice for blast wave calcu

ISSN:0271-2091    

DOI:10.1002/fld.1650090103

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe turbulent momentum transport phenomena in a two‐dimensional mixing layer are investigated numerically by a discrete vortex method. The numerical model and calculations are verified through a comparison with existing numerical simulations and experimental measurements. The main emphasis is placed on the exploration of the detailed time‐dependent instantaneous local momentum fluctuations and on the comparison of numerical results with available experimental measurements. The current simulations confirm qualitatively the various trends in the turbulent momentum flux and fluctuating components of the velocity in the mixing layer found with several experimental results. The study shows that similarity exists in turbulent momentum quantities along the axial direction of the mixing layer. The calculations also show a definite correlation between the passage of a large‐scale structure and a burst in the turbulent momentum flux. The probability density functions of the fluctuating quantities are shown to be mostly Gaussian‐like, with only a few exc

ISSN:0271-2091    

DOI:10.1002/fld.1650090104

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractVelocity–pressure integrated and consistent penalty finite element computations of high‐Reynolds‐number laminar flows are presented. In both methods the pressure has been interpolated using linear shape functions for a triangular element which is contained inside the biquadratic flow element. It has been shown previously that the pressure interpolation method, when used in conjunction with the velocity‐pressure integrated method, yields accurate computational results for high‐Reynolds‐number flows. It is shown in this paper that use of the same pressure interpolation method in the consistent penalty finite element method yields computational results which are comparable to those of the velocity–pressure integrated method for both the velocity and the pressure fields. Accuracy of the two finite element methods has been demonstrated by comparing the computational results with available experimental data and/or fine grid finite difference computational results. Advantages and disadvantages of the two finite element methods are discussed on the basis of accuracy and convergence nature. Example problems considered include a lid‐driven cavity flow of Reynolds number 10 000, a laminar backward‐facing step flow and a laminar flow through a

ISSN:0271-2091    

DOI:10.1002/fld.1650090105

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractSteady 2D Euler flow computations have been performed for a wind tunnel section, designed for research on transonic shock wave–boundary layer interaction. For the discretization of the steady Euler equations, an upwind finite volume technique has been applied. The solution method used is collective, symmetric point Gauss–Seidel relaxation, accelerated by non‐linear multigrid. Initial finest grid solutions have been obtained by nested iteration. Automatic grid adaptation has been applied for obtaining sharp shocks. An indication is given of the mathematical quality of four different boundary conditions for the outlet flow. Two transonic flow solutions with shock are presented: a choked and a non‐choked flow. Both flow solutions show good shock capturing. A comparison is made with experimental

ISSN:0271-2091    

DOI:10.1002/fld.1650090106

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractUsing weighted discretization with the modified equivalent partial differential equation approach, several accurate finite difference methods are developed to solve the two‐dimensional advection–diffusion equation following the success of its application to the one‐dimensional case. These new methods are compared with the conventional finite difference methods in terms of stability and accuracy. The new methods are more accurate and often more stable than the conventional sc

ISSN:0271-2091    

DOI:10.1002/fld.1650090107

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractIt is generally accepted that mixed and penalty finite element methods can routinely solve the incompressible Navier–Stokes equations. This paper shows by means of simple examples that problems can arise even for the simpler Stokes equations. The causes of the problem fall in either of two categories: round‐off and ill conditioning, or a poor choice of pressure discretization. Nonsensical solutions can be obtained. Computation of the discrete divergence of the flow field is a simple and powerful tool to diagnose such conditions. In the first part of the paper several simple techniques for minimizing the effect of round‐off are reviewed. In the second part it is shown that, for coupled flow problems, care must be exercised in the choice of the pressure approximation. A unified treatment of various observations by different workers is presented. This should prove useful for general users of the finite element m

ISSN:0271-2091    

DOI:10.1002/fld.1650090108

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractFlux splitting is applied to the convective part of the steady Navier–Stokes equations for incompressible flow. Partial upwind differences are introduced in the split first‐order part, while central differences are used in the second‐order part. The discrete set of equations obtained is positive, so that it can be solved by collective variants of relaxation methods. The partial upwinding is optimized in the same way as for a scalar convection–diffusion equation, but involving several Peclet numbers. It is shown that with the optimum partial upwinding accurate results can be obtained. A full multigrid method in W‐cycle form, using red–black successive under‐relaxation, injection and bilinear interpolation, is described. The efficiency of this method is

ISSN:0271-2091    

DOI:10.1002/fld.1650090109

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650090110

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650090111

出版商:John Wiley&Sons, Ltd    

年代:1989

数据来源: WILEY