Influence of boundary-layer separation of aerofoil under small angle of attack on the numerical simulation

Based on the three-dimensional RANS,a numerical simulation on NREL S809 airfoil was carried out with RNG k-e and RSM turbulence models,respectively.The airfoil aerodynamic performance was proved and a comparison of the results from the two models was made.The results showed that airfoil boundary layer separates with the increasing angle of attack.Before the separation,the simulation results are basically consistent with the experimental data despite some errors.However,the differences between simulation results and experimental data become much larger after separation.Along with the increase of angle of attack,the turbulent flow is intensified and errors of simulation results also increase.Therefore,it proved that the separation of aerofoil boundary layer is a vital factor which influences the simulation results.