高雷诺数下的翼型绕流LBM数值模拟

采用格子Boltzmann方法(LBM)的二维9速度(D2Q9)模型和贴体网格,通过引入非均匀网格插值方法和非平衡态外推边界处理,分别结合Baldwin-Lomax(B-L)湍流模型和Spalart-Allmaras(S-A)湍流模型,对高雷诺数Re≥5×105下的NACA0012翼型绕流进行了数值模拟和对比研究,两者的结果与CFL3D的结果和实验结果均吻合的很好,相比之下,采用S-A模型能更好地预测失速迎角,其处理分离流动的能力要强于B-L模型。改进后的LBM适用于非均匀贴体网格,曲边边界,计算简单,并可应用于更复杂的高雷诺数流动中。

Simulation of High Reynolds Number Flow Around Airfoil by Lattice Boltzmann Method

Simulation of a high Reynolds number flow(Re≥5×10~5)around an airfoil(NACA00l2)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 eurvilinear boundary,and its calculation is simple.It can be applied to more complex high Reynolds number flows.