Adaptive prismatic-tetrahedral grid refinement and redistribution for viscous flows

Abstract

A hybrid grid adaptive algorithm that combines grid refinement and redistribution suitable for three-dimensional viscous flow simulations is presented. The flow domain is discretized with both prismatic and tetrahedral elements. The prismatic region comprises successive layers of semistructured prisms that encompass regions close to the wall where the viscous effects are dominant. The grid outside the prismatic region is tessellated with tetrahedra. A hybrid grid adaptation scheme that implements local refinement and redistribution strategies is developed to provide optimum meshes for viscous flow computations. Grid refinement on a hybrid grid is a dual adaptation scheme that couples isotropic division of tetrahedra and directional division of prisms. The directional division of prisms is essentially a two-dimensional grid refinement scheme that results in a significant reduction in required computing resources. The grid adaptive solver yields accurate results as compared with a globally refined grid with reduced computing resources.