Large eddy simulation of turbulent flow around a wall mounted hemisphere

Turbulent air flow around a wall-mounted hemisphere is investigated numerically for Reynolds numbers equal to 36,000 and 64,000. Large eddy simulation (LES) is used to simulate the flow field and results are compared with wind tunnel measurements and computations from RNG k–ε modeling. The shortcoming of the RANS model is reported and the LES advantages are highlighted for modeling of such external flows around a bluff body. Various subgrid scale models are considered and compared for LES simulation. Using the numerical simulation results, streamlines at different sections of the flow domain are presented and pressure and velocity distribution at different locations over the hemisphere are plotted and compared. It is shown that the LES model can be properly used to obtain the complex flow field behind the hemisphere where the RANS model fails to predict the flow field accurately. Among subgrid scale models the prediction of kinetic energy turbulence model shows better agreement with the experimental data.