A MIXED ELEMENT TYPE UNSTRUCTURED GRID METHOD FOR SIMULATING 3D TURBULENT FLOWS

摘要

In this paper, a method is presented for the viscous flow simulations by solving the Navier-Stokes equations on three-dimensional mixed element type unstructured grids. Pirzadeh's advancing-layer method is modified to generate high quality mixed prismatic/pyramidal/tetrahedral element type unstructured grids in boundary-layer region, and advancing-front method is used to construct isotropic tetrahedral grids in the residual flow region. Three-dimensional Navier-Stokes equations are solved by using a cell-centered finite-volume method with AUSM~+—up scheme and Spalart-Allmaras one-equation turbulence model. Time is advanced by an implicit Gauss-Seidel relaxation procedure which is constructed by using the first-order linearizing of flux vector and the maximal eigenvalue splitting of flux Jacobi matrix. The assessments of the presented method are derived from the simulation of viscous flow problems around the ONERA M6 wing. DLR-F6 wing-body and DLR-F6 wing-body-pylon-nacelle configuration.