Output Based Grid Adaptation for ViscousFlow

Reserach Notes, 18th International Meshing Roundtable, Springer-Verlag, pp.1-5, October 25-28 2009

IMR
PROCEEDINGS

18th International Meshing Roundtable
Salt Lake City, UT, USA.
October 25-28, 2009

Massachusetts Institute of Technology,
jandren@mit.edu
NASA Langley Research Center, Computational AeroSciences Branch,
Mike.Park@NASA.gov

Introduction
Output (adjoint) based adaptation is a method that has been used to automate the unstructured grid generation task of inviscid [3] and two-dimensional (2D) turbulent [6,7] flow simulation. This project challenges existing three dimensional (3D) techniques to produce strongly anisotropic grids for modeling the boundary layer on a flat plate. Elements with large face angles can cause difficulties for the diffusion operator employed in this study [1], so a range of Reynolds numbers are explored to quantify the accuracy of the solutions on the output adapted grids. Laminar and turbulent flows are simulated on an extruded flat plate to exercise the 3D algorithm on a case with a know solution. Regular, fully adapted, and hybrid unstructured tetrahedral grids are used to examine the ability of different grid constructions to reproduce Blasius or empirically derived velocity profiles. The hybrid approach retained the original regular tetrahedral grid near the flat plate and adapted the grid outside of this region. This approach produced similar velocity profiles to the regular grids and better results than the fully adaptive cases for the highest Reynolds number cases.

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