Adaptive hybrid grid methods

Abstract

An adaptive refinement and redistribution method is presented for use on hybrid grids composed of prismatic, pyramidal and tetrahedral elements. The combined refinement and redistribution scheme minimizes the computational time and memory required for the solver and maximizes the numerical accuracy. Grid refinement is achieved via a priori source placement and also solution based splitting of the edges of the grid elements. The prismatic and pyramidal elements are divided directionally and the tetrahedral elements may be refined isotropically or directionally. The prismatic grid redistribution scheme attracts or repels points that are close to the wall surface so as to better capture boundary layers. A method is developed to place newly created boundary nodes on the actual splined surface instead of the previous discretized surface. This ensures that the grid refinement always represents the geometric model accurately. Several examples are presented to demonstrate the a priori source placement, the solution based grid refinement and the prismatic grid redistribution.