高超声速边界层转捩模型横流效应修正与应用

Crossflow modification of transition model for hypersonic boundary layer and its application

三维边界层在高超声速飞行器中普遍存在,转捩过程受到横流不稳定性的显著影响而出现复杂的转捩形态特征。为了提高转捩模型对高超声速三维边界层转捩现象的预测能力,在与SST湍流模型耦合求解的γ-Re转捩模型基础上,提出了一种基于当地流场变量的横流效应修正方法。以椭圆锥外形为研究对象,开展了转捩模型横流效应修正方法的分析、验证及应用。数值模拟结果表明,椭圆锥外形高超声速边界层流动存在显著的横流特征,在模型中部产生横流转捩现象。构造的横流雷诺数判据能够有效表征三维边界层流动的横流效应,提出的转捩模型横流效应修正方法提高了横流转捩的预测能力,通过标定修正模型参数获得了与风洞试验数据和精细模拟接近的转捩形态特征。风洞试验及飞行试验数据验证表明,提出的转捩模型横流效应修正方法对高超声速三维边界层转捩预测具有较好的应用效果。

The three-dimensional boundary layer is ubiquitous in hypersonic vehicles, and transition process is significantly affected by the crossflow instability, resulting in complex transition patterns. To improve the prediction ability of the transition model for hypersonic three-dimensional boundary layer, on the basis of γ-Retransition model coupled with the SST turbulence model, a crossflow effect modification method based on local flow variables is proposed. The analysis, verification and application of the crossflow modification method are carried out on the elliptical cone. The numerical simulation results show significant crossflow features in the hypersonic boundary layer on the elliptical cone, and crossflow transition occurs in the middle of the model. It is demonstrated that, the crossflow Reynolds number criterion can effectively characterize the crossflow effect of the three-dimensional boundary layer, and the proposed crossflow modification method improves the prediction ability for crossflow transition. The transition patterns close to those of the wind tunnel experimental data and high-fidelity simulation are obtained by calibration of the crossflow modification parameters. The verification of wind tunnel test and flight test data indicates that, the proposed transition model crossflow modification method achieves good application effect on the transition prediction of hypersonic three-dimensional boundary layer.