Large-scale numerical simulation of unsteady flow field in a half-ducted propeller fan using lattice Boltzmann method

Recently, the lattice Boltzmann method (LBM) is being applied in turbomachinery field, regarded as a good candidate for tool of flow simulation as well as aerodynamic sound analysis. For better prediction of broadband noise with high frequecy, which is generally generated in high Reynolds number flows, not only high grid resolution is required to capture very small eddies of the sound source inside the turbulent boundary layer, but also the computation of acoustic field is often needed. In such case, the direct simulation of flow field and acoustic field is straightforward and effective. However, the computational cost becomes extremely expensive. Moreover, for low Mach number flows the compressible Navier-Stokes simulation not only requires high-order scheme which is unsuitable for parallel computation, but also suffers from stiff problem. LBM is suitable for such simulation thanks to its advantages. In the present study, a large-scale numerical simulation of flow field around a half-ducted propeller fan is conducted with LBM, and its result is validated by comparing with the experimental result.