Abstract: The wall function approach is implemented in the National Numerical Wind Tunnel software coupling the SST k-ω model through an iteration of the friction velocity and update of the turbulence viscosity at the virtual point to modify the wall shear stress. Verification of this approach by the compression corner and the high-speed flight vehicle shows that: the wall function approach with the coarse mesh (y⁺≤200) significantly improves the velocity distribution of the turbulence boundary layer and skin-friction with a 75% decrease in the computation time compared with the fine mesh. For the complex flight vehicle, the total mesh amount decreases by about 38% when the wall distance widens between the wall layers, and the CPU time consumption decrease by 60% with the same numerical setup. The shock/boundary layer interaction exists near the inlet, where similar flow separation and shock reflection are obtained for both the fine mesh and coarse mesh with the wall function approach. Comparison of axial force variation shows that the adoption of the wall function reduces the prediction error of skin friction from 40% to 4%, and the whole axial force from 15% to 2%. Overall, the wall function approach is an efficient numerical method for the turbulence force prediction of flight vehicles.

Key words: wall function, turbulence viscosity, SST k-ω model, skin friction, high-speed flight vehicles