通过子迭代的方式计算摩擦速度, 更新虚拟点湍流黏性系数实现对壁面剪切应力的修正, 耦合SST k-ω两方程模型, 在国家数值风洞软件平台上实现了壁面函数程序模块。通过压缩拐角和高速飞行器典型算例进行考核, 初步数值实验结果表明：压缩拐角算例壁面函数在无量纲壁面距离y+≤200范围内, 均准确预测湍流边界层速度分布, 可显著提高粗网格上壁面湍流边界层和壁面摩擦系数的预测精度, 且壁面函数使用粗网格最多可节约75%的计算时间；对于复杂外形, 附面层网格间距变宽, 可使得整体网格减少约38%的网格总量, 在相同的计算设置情况下可节约60%的计算时间。唇口附近出现明显的激波边界层干扰现象, 使用壁面函数后稀网格和密网格得到流场中分离、激波反射相同, 且分离区最高压力系数偏差从15%降低到2%。从粗网格和密网格全机轴向力系数比较来看, 使用壁面函数后摩阻预测偏差可从40%下降到4%。整体来看, 壁面函数的引入提供了一种高效的飞行器湍流流动气动力预测方法。
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.
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