Grid Control of Viscous Unstructured Meshes Using Optimization

Mandar S. Sahasrabudhe, Steve L. Karman Jr., and W. Kyle Anderson
UT SimCenter at Chattanooga, The University of Tennessee at Chattanooga, Chattanooga, Tennessee, 37403

A mesh smoothing approach is described that uses an optimization technique to improve the quality of unstructured viscous meshes. The cost function for the optimization is based on element condition number. The cost function prohibits element inversion and attempts to imposed a desired spacing and growth rate of elements in viscous layers. The method can be run using global or local optimization. If local optimization is used a cuto threshold can be employed to restrict the optimization to the nodes with the highest cost function, reducing the run times considerably. Several examples of optimization of three-dimensional viscous meshes are included, with improvements in several quality metrics noted.