Detached-eddy simulation of wing-tip vortex in the near field of NACA 0015 airfoil

In the present study, the formation of the wing-tip vortex from a rectangular NACA0015 wing with a square tip at the Reynolds number of 1.8×105 and the angles of attack (AOA) α = 8o and 10o were simulated with an incompressible detached eddy simulation (DES) method and the Reynolds averaged Navier-Stokes (RANS) equations with the SA model respectively. Numerical results were compared with experimental results to validate the capability of the employed methods in resolving tip vortex flows. The results show that DES model could capture the complicated three-dimensional structures in the vortex, and the streamwise vorticity and the cross-flow velocity agree with the experiment results quite well, but RANS-SA model with the same grid as that of DES failed to capture the correct structures and under-predicted the streamwise vorticity in the vortex by 40%. The present study suggests that under the same calculation cost, DES but not RANS-SA could be used to effectively predict the flow characteristics in tip vortex.