Solution of the Euler- and Navier-Stokes Equations on Hybrid Grids.

Abstract

A three-dimensional finite volume scheme is presented. The scheme is based on the employment of hybrid grids, containing tetrahedral as well as prismatic cells. The application of hybrid grids offers the possibility to combine the flexibility of tetrahedral meshes with the accuracy of regular grids. An algorithm to compute an auxiliary grid of control volumes for the entire computational domain was formulated. The dual mesh technique guarantees conservation in the entire flow field even at interfaces between prismatic and tetrahedral domains and enables the employment of an accurate upwind flow solver. Convergence to the steady state can be accelerated by a multigrid algorithm based on the agglomeration of control volumes. The formulation of such algorithm is presented. The code is tested on several viscous and inviscid cases for transonic and subsonic flows.