Parallel mesh multiplication and adaptation technique for turbulent flow simulation using unstructured meshes

Abstract

In this paper, we report the development of a parallel mesh multiplication code to subdivide a base mesh (containing tetrahedral, pyramids, prisms or hexahedral) into a finer mesh without user intervention, taking care of the quality of refined meshes generated by the algorithm. First, a coarse mesh is generated with an unstructured mesh generator and subdivided to the level of resolution needed for the simulation. On the refinement process of tetrahedral elements, geometrical properties are taking into account in order to preserve the shape quality of the subdivided elements. Then, the mesh is conformed on the solid surfaces to the original geometry, since linear subdivision ignores surface curvatures, and interior points of the mesh are adapted using Radial Basis functions, due to the surface correction. Moreover, a smoothing algorithm for tetrahedral mesh is applied to improve the mesh quality according to element geometry metric or based in minimize numerical errors in the CFD solution computed with unstructured meshes. Finally, the applicability of this method is shown on the numerical simulation of the turbulent flow over an Ahmed car at Reh = 7.68 × 10e5.