Developments in Efficient Mesh Connectivity for Overset Grids

Speaker: William M. Chan, Applied Modeling & Simulation Branch, NASA Ames Research Center
August 13, 2015

Presentation

Abstract

An automatic and efficient method to determine appropriate hole cuts based on distances to the wall and donor stencil maps for overset grids is presented. A new robust procedure is developed to create a closed surface triangulation representation of each geometric component for accurate determination of the minimum hole. Hole boundaries are then displaced away from the tight grid-spacing regions near solid walls to allow grid overlap to occur away from the geometry surface where cell sizes from neighboring grids are more comparable. The placement of hole boundaries is efficiently determined with minimal user input using a mid-distance rule and Cartesian maps of potential valid donor stencils. Application of this procedure typically results in a spatially-variable offset of the hole boundaries from the minimum hole with only a small number of orphan points remaining. Test cases on complex configurations are presented to demonstrate the new scheme. The new method has been implemented into a software tool called Chimera Components Connectivity Program. Software features and OpenMP parallelization scaling issues are discussed.

Biography

William obtained his B.S. in Mathematics from Southampton University in the U.K., and M.S. and Ph.D. from the Mechanical Engineering Department of Stanford University. His primary interest is on the development of algorithm and software for overset grid pre-processing and post-processing. He is the principal developer of many of the modules of the Chimera Grid Tools software package which has been distributed to over 700 organizations in U.S. government laboratories, industry and universities. Since working at NASA Ames, he has supported high fidelity CFD simulations of the Space Shuttle Launch Vehicle, subsonic and supersonic fixed wing, and rotor wing vehicles, various turbopumps and liquid rocket sub-systems, and a variety of space launch vehicles from the Constellation and Space Launch Systems programs.

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