摘要:

The effect of artificial diffusion on discrete shock structures is examined for a family of schemes which includes scalar diffusion, convective upwind and split pressure (CUSP) schemes, and upwind schemes with characteristic splitting. The analysis leads to conditions on the diffusive flux such that stationary discrete shockscan contain a single interior point. The simplest formulation which meets these conditions is a CUSP scheme in which the coefficients of the pressure differences are fully determined by the coefficient of convective diffusion. It is also shown how both the characteristic and CUSP schemes can be modified to preserve constant stagnation enthalpy in steady flow, leading to four variants, the E and H-characteristic schemes, and the E and H-CUSP schemes. Numerical results are presented which confirm the properties of these schemes.

ISSN:1061-8562    

DOI:10.1080/10618569508940734

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We present a general, parallelizable, load balancing algorithm for unstructured grid-based problems that belong to the so-called diffusion class and employ a give-and-take concept among neighbouring subdo-mains. The algorithm is found to converge very quickly to almost perfect load balance while minimizing the surface-to-volume ratio of the domains. The algorithm can be used for problems whose cost grows nonlinearly with the number of elements, because it measures continuously the computational cost to be incurred for each subdomain. This is an advantage over the recursive bisection algorithms currently in use, which assume a linear relationship between the computational cost and the number of elements.

ISSN:1061-8562    

DOI:10.1080/10618569508940735

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The dynamics of unconfined, spatially developing shear layers is studied through the numerical solutions of the time-dependent Euler equations using a second-order Godunov scheme. The effects of density and velocity variations between the two streams of the shear layer are studied and color graphics are used to show more clearly the entrainment process of the surrounding streams. The calculations demonstrate that the evolution of the mean flow is dominated by two-dimensional, inviscid effects. The r.m.s. fluctuating velocity and density profiles are in good agreement with the measurements of Oster and Wygnanskiand of Konrad, except for the peak value of thev′ profile.

ISSN:1061-8562    

DOI:10.1080/10618569508940736

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A finite volume/finite difference method based on Ni's multigrid formulation is introduced for the solution of Maxwell's equations. The scheme is presented for the cases of transverse magnetic scattering from two-dimensional circular and square cylinders, as well as from NACA 0012 airfoil. The codes are validated against the traditional Method of Moments, which is analogous to a panel method in CFD. The circular cylinder scattering is compared to the analytical series solution for better understanding how the roles of numerical dispersion and dissipation errors affect the solution. The reflecting boundary conditions are modeled by the idea of inducing fields inside the conductor and a method of modeling the singularities that arise at a sharp corner is presented. Absorbing boundary conditions are modeled by integrating along the characteristic compatibility equations in the direction of the outgoing wave.

ISSN:1061-8562    

DOI:10.1080/10618569508940737

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A variational principle for grid generation is described. A unique solution of the variational problem is represented by a quasi-isometric mapping of the unit square onto a physical domain. The variational principle is based on the theory of conformal mapping and the geometry of the surface of constant curvature.

ISSN:1061-8562    

DOI:10.1080/10618569508940738

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper presents a hybrid spectral/finite volume method for steady-state compressible viscous flows. The method is evaluated for accuracy via test cases for various Mach numbers. The domain is divided into a viscous region and an inviscid region. The viscous region uses the full Navier-Stokes equations, while the inviscid region employs the Euler equations. A high order Chebyshev collocation spectral method is developed for the viscous region to resolve boundary layers. This method avoids the dense grids needed by finite-volume methods to resolve the viscous areas. A low order finite-volume method based on a Lax-Wendroff type scheme is employed for the inviscid region. A special interface formulation is developed for coupling the spectral with the finite-volume method. Comparisons with analytic results as well as convergence histories are presented.

ISSN:1061-8562    

DOI:10.1080/10618569508940739

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor