Accession Number : ADA302603

Title :   A Unified Multigrid Solver for the Navier-Stokes Equations on Mixed Element Meshes.

Descriptive Note : Contractor rept.,

Corporate Author : INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA

Personal Author(s) : Mavriplis, D. J. ; Venkatakrishnan, V.

PDF Url : ADA302603

Report Date : JUL 1995

Pagination or Media Count : 27

Abstract : A unified multigrid solution technique is presented for solving the Euler and Reynolds averaged Navier Stokes equations on unstructured meshes using mixed elements consisting of triangles and quadrilaterals in two dimensions, and of hexahedra, pyramids, prisms and tetrahedra in three dimensions. While the use of mixed elements is by no means a novel idea, the contribution of the paper lies in the formulation of a complete solution technique which can handle structured grids, block structured grids, and unstructured grids of tetrahedra or mixed elements without any modification. This is achieved by discretizing the full Navier Stokes equations on tetrahedral elements, and the thin layer version of these equations on other types of elements, while using a single edge based data structure to construct the discretization over all element types. An agglomeration multigrid algorithm, which naturally handles meshes of any types of elements, is employed to accelerate convergence. An automatic algorithm which reduces the complexity of a given triangular or tetrahedral mesh by merging candidate triangular or tetrahedral elements into quadrilateral or prismatic elements is also described. The gains in computational efficiency afforded by the use of nonsimplicial meshes over fully tetrahedral meshes are demonstrated through several examples.

Descriptors :   *FINITE ELEMENT ANALYSIS, *NAVIER STOKES EQUATIONS, ALGORITHMS, COMPUTATIONS, LAYERS, EFFICIENCY, MESH, GRIDS(COORDINATES), SOLUTIONS(GENERAL), PRISMATIC BODIES, TRIANGLES.

Subject Categories : Fluid Mechanics
      Numerical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE