Construction of CAD-based unstructured mesh models for 3D Navier-Stokes simulations

Abstract

There is little doubt that in the future the efficient simulation of a wide variety of practical, complex geometry flows will take place using CFD based on unstructured mesh systems. There is also little doubt that practical, three dimensional Navier-Stokes simulations cannot proceed unless these unstructured mesh systems support highly stretched, highly anisotropic computational cells. For nearly a decade unstructured meshes have been developed and used for 3D inviscid flow around and through increasingly complex flow domains: see for example the very early efforts of Jameson et al (Ref. 1) and Peraire et al (Ref. 2). However, most mesh generating technology has sought, or been produced by, algorithms which assume, nearly isotropic, equilateral meshes. By contrast, unstructured meshes for 3D viscous flows have been produced in an ad hoc way by various short-term artifices, including simply shredding stretched structured meshes into tetrahedrons (Ref. 3). This paper presents a new procedure which can generate highly stretched viscous meshes of tetrahedrons for essentially arbitrary 3D configurations.