Abstract:

Simulation of a high Reynolds number flow (Re≥5×105) around an airfoil (NACA0012) using the Lattice Boltzmann method (LBM) is performed in this article. The present method chooses a two-dimensional 9-velocity (D2Q9) model and uses a non-uniform body-fitted mesh. Originally, the LBM is an incompressible flow solver in orthogonal coordinates. In order to resolve the boundary layer of the airfoil accurately, the algorithm is extended to generalized coordinates. Meanwhile, a non-equilibrium extrapolation scheme for the wall boundary condition is adopted. In order to calculate high Reynolds number flows, the present method is combined with the Baldwin-Lomax (B-L) turbulence model and the Spalart-Allmaras (S-A) turbulence model respectively. The results agrees well with the CFL3D solver results and experimental data. Compared with the B-L model, the S-A model can give more accurate prediction of the static stall angle and show better ability of separated flow simulation. The present method is suitable for problems of non-uniform body-fitted mesh and curvilinear boundary, and its calculation is simple. It can be applied to more complex high Reynolds number flows.

Key words: lattice Boltzmann method, high Reynolds number flow, non-uniform, body-fitted mesh, airfoil