A VARIATIONAL MULTISCALE METHOD WITH MULTIFRACTAL SUBGRID-SCALE MODELING FOR LARGE-EDDY SIMULATION OF TURBULENT FLOW
Volker Gravemeier, U. Rasthofer · Blucher Mechanical Engineering Proceedings · 2014
A variational multiscale method with multifractal subgrid-scale modeling is proposed for large-eddy simulation of turbulent flow.In the multifractal subgrid-scale modeling approach, the subgrid-scale velocity is evaluated from a multifractal description of the subgrid-scale vorticity, which is based on the multifractal scale similarity of gradient fields in turbulent flow.The multifractal subgrid-scale modeling approach is integrated into a variational multiscale formulation, demonstrating a new field of application of the variational multiscale concept.In addition, the application of the multifractal subgrid-scale modeling approach to wall-bounded turbulent flow is considered in this study.For this purpose, a nearwall limit of the multifractal subgrid-scale modeling approach is developed.The novel computational approach of multifractal subgrid-scale modeling within a variational multiscale formulation is then applied to turbulent flow over a backward-facing step.The results confirm a very good performance of the proposed method, and improved results are obtained compared to a dynamic Smagorinsky model and a residual-based variational multiscale method.