Reordering of 3-D hybrid unstructured grids for vectorized LU-SGS Navier-Stokes computations

3-D Navier-Stokes and Euler computations on unstructured hybrid grids are discussed. Implicit LUSGS (Lower-Upper Symmetric Gauss-Seidel) approximate factorization is implemented to arbitrary 3-D hybrid unstructured grid. Grid reordering algorithm for efficient implementation of LU-SGS is proposed. This reordering provides good balance between lower and upper matrices and makes the code vectorizable. The implicit scheme is applied together with finite volume cell-vertex upwind scheme based on Venkatakrishnan's limiter and HLLEW (Harten-Laxvan Leer-Einfeldt-Wada) Riemann solver. Applications of the method to 3-D transonic and hypersonic flow problems demonstrate its efficiency.