Evaluation of multigrid solutions for turbulent flows

A multigrid methodology has been recently developed in a NASA solver, FUN3D, and successfully applied for a wide range of turbulent flows, from simple two-dimensional geometries to realistic three-dimensional configurations. The methodology is applicable to structuredand unstructured-grid solutions and includes both regular and agglomerated coarse meshes. Significant speed-ups over single-grid computations have been demonstrated. In the current work, we report on a detailed evaluation of the solver performance in computing benchmark turbulent flows. For those benchmark computations, multigrid solutions are compared with the corresponding single-grid solutions in terms of time-tosolution characteristics measured in the same computing environment. Multigrid efficiency enables a detailed grid-refinement study of a turbulent flow around an airfoil that is reported in the Appendix.

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