Hybrid Adaptation Method and Directional Viscous Multigrid with Prismatic-Tetrahedral Meshes
نویسنده
چکیده
A solution adaptive scheme with directional multigrid for viscous computations on hybrid grids is presented. The ow domain is discretized with prismatic and tetrahedral elements. The use of hybrid grid enables the solver to compute accurate solutions with relatively less memory requirement than a fully unstructured grid. Further, employing prisms to discretize the full Navier-Stokes equations and tetrahedra for Euler equations renders the solver equation-adaptive. A hybrid grid adaptation scheme that implements h-reenement and redistribution strategies is developed to provide optimum meshes for viscous ow computations. Grid reenement is a dual adaptation scheme that couples 3-D, isotropic division of tetrahedra and 2-D, directional division of prisms. The grid adaptive solver yields accurate results as compared to a globally reened grid with reduced computing resources. A directional viscous multigrid scheme is developed to accelerate convergence to steady-state. The method is suitable for the directional viscous ow gradients. Further, a simple technique is used to generate coarser grids for multigrid which reduces memory requirements by avoiding intergrid transfer pointers. Results are presented to validate the adaptive hybrid viscous solver and show grid inde-pendency of the solutions obtained. Comparisons of residual histories are shown to demostrate the performance of the directional multigrid scheme.
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