Grid-independent large-eddy simulation

Sanjeeb Bose, Stanford University

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The governing equations for large-eddy simulation are derived from the application of a low-pass filter to the Navier-Stokes equations. It is often assumed that discrete operations performed on a particular grid act as an implicit filter causing results to be sensitive to the mesh resolution. Alternatively, explicit filtering separates the filtering operation from the underlying mesh distribution, thereby eliminating grid sensitivities. We investigate the use of explicit filtering in large-eddy simulation in order to obtain numerical solutions that are grid independent and are not influenced by numerical errors. Convergence to grid-independent solutions is demonstrated for turbulent channel flows over a range of Reynolds numbers. The performance of subfilter scale models isolated from numerical errors is evaluated. Further extensions and application to large scale computation of complex geometries on unstructured meshes will be shown.

Abstract Author(s): Sanjeeb T. Bose and Parviz Moin