摘要:

AbstractA very simple linearization of the solution to the Riemann problem for the steady supersonic Euler equations is presented. When used locally in conjunction with the Godunov method, computing savings by a factor of about four relative to the use of exact Riemann solvers can be achieved. For severe flow regimes, however, the linearization loses accuracy and robustness. We then propose the use of a Riemann solver adaptation procedure. This retains the accuracy and robustness of the exact Riemann solver and the computational efficiency of the cheap linearized Riemann solver. Numerical results for two‐ and three‐dimensional test problems are presen

ISSN:0271-2091    

DOI:10.1002/fld.1650160302

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractAn efficient semi‐implicit finite element model is proposed for the simulation of three‐dimensional flows in stratified seas. The body of water is divided into a number of layers and the two horizontal momentum equations for each layer of water are first integrated vertically. Nine‐node Lagrangian quadratic isoparametric elements are employed for spatial discretization in the horizontal domain. The time derivatives are approximated using a second‐order‐accurate semi‐implicit time‐stepping scheme. The distinguishing feature of the proposed numerical scheme is that only nodal values on the same vertical line are coupled. Two test cases for which analytic solutions are available are employed to test the proposed scheme. The test results show that the scheme is efficient and stable. A numerical experiment is also included to compare the proposed scheme with a finite diff

ISSN:0271-2091    

DOI:10.1002/fld.1650160303

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper investigates the use of defect correction procedures for the solution of finite volume approximations to systems of conservation laws. Particular emphasis is laid on the order of accuracy obtained after a fixed finite number of iterations. It is shown that a high order of accuracy may be achieved after only one defect correction iteration, involving two inversions of a stable lower‐order‐accurate operator. However, this result is found to be critically dependent on the consistency of the lower‐order operator, a property which does not always hold for conservative finite volume discretizations. Through numerical experiments, the lack of consistency of these schemes is found to inhibit severely the finite termination property of the defect correction process. Results are presented for linear advection, Poisson's equation, and the Euler equa

ISSN:0271-2091    

DOI:10.1002/fld.1650160304

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA computer simulation is made of cellular convection in a moist atmosphere in an endeavour to obtain a computer model which more closely approximates the observed modes of convection. A finite element Galerkin technique, with Taylor approximation and Crank‐Nicolson, is employed and comparisons are made with the author's earlier finite element models of convection in an absolutely unstable atmosphere and with finite difference models. It is found that the inclusion of the moisture effects alters the structure of a cell to that of a narrow ascending region and a wider descending region with the former of larger velocities than the latter, and also alters the preferred mode of convection by increasing the aspect ratio. This more closely resembles that which is observed in the atmospher

ISSN:0271-2091    

DOI:10.1002/fld.1650160305

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA complete boundary integral formulation for steady compressible inviscid flows governed by non‐linear equations is established by using the specific mass flux as a dependent variable. Thus, the dimensionality of the problem to be solved is reduced by one and the computational mesh to be generated is needed only on the boundary of the domain. It is shown that the boundary integral formulation developed in this paper is equivalent of the results of distributions of the fundamental solutions of the Laplacian operator equation with a different order along the boundaries of the domain. Hence, we have succeeded in establishing the fundamental‐solution method for compressible inviscid flows governed by non‐linear equa

ISSN:0271-2091    

DOI:10.1002/fld.1650160306

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe development of asymmetric wake behind an aerofoil in turbulent incompressible flow has been computed using finite volume scheme for solving two‐dimensional Navier‐Stokes equations along with thek‐ε model of turbulence. The results are compared with available experimental data. It is observed that the computed shift of the point of minimum velocity with distance is sensitive to the prescribed value of the normal component of velocity at the trailing edge of the aerofoil. Making the model constantCuas a function of streamline curvature and changing the production term in the equation for ε, has only marginal influence on the

ISSN:0271-2091    

DOI:10.1002/fld.1650160307

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractWe show that the continuous (in time) form of the projection‐3 scheme proposed in Reference 2 is not a proper approximation of the unsteady Navier‐Stokes equations. Hence, the projection‐3 scheme and its variants are not appropriate for the numerical computation of the Navier‐Stokes eq

ISSN:0271-2091    

DOI:10.1002/fld.1650160308

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650160309

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650160301

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY