A hybrid immersed boundary/wall-model approach for large-eddy simulation of high-Reynolds-number turbulent flows

摘要

We propose an improved hybrid immersed boundary (IB)/wall-model approach for high-Reynolds-number large-eddy simulations (LES). A preliminary test shows that the existing model that modifies sub-grid viscosity based on the mixing-length model leads to deviation of the wall shear stress when implemented at high Reynolds numbers. To correct the deviation of the wall shear stress at high Reynolds numbers, the sub-grid viscosity at the border of the IB force is reconstructed based on the near-wall balance of shear stress. A correct value for wall shear stress can thus feed back to the border of the IB force and LES solution. The proposed method is tested on several numerical examples, namely a turbulent pipe-flow with friction Reynolds numbers up to 1.0 x 10(5), turbulent flow over a circular cylinder with Reynolds numbers up to 1.4 x 10(5), turbulent flow over a sphere with Reynolds numbers up to 1.0 x 10(4), and turbulent flow over a pitching airfoil with a Reynolds number of 4.8 x 10(4). The results provide reasonable predictions compared with previous studies.