Large Eddy Simulation of Turbulent Air Flow Over a Surface Mounted Hemisphere

Turbulent air flow around a surface mounted hemisphere is investigated numerically. The flow field has been simulated using Large Eddy Simulation (LES) technique. Using LES results, variations of flow velocity at various sections along the midplane are presented and compared with the wind tunnel measurements. Also the results of LES are compared with a RANS model (k-ε RNG). It is concluded that LES with the proper grid resolution is capable to capture the complex features of the flow especially in the separation bubble formed behind the hemisphere. The LES results are in a better agreement with experimental data compared with k-ε RNG model. Also various SGS models for LES technique are tested and the predictions of these models are compared.