激波与边界层干扰下高超声速气动热的高精度数值模拟

The background of this study is its possible applications to thermal protection of hypersonic vehicles. A high-resolution method is developed to simulate the local transient high heat-flux within shock wave and boundary layer interaction, which is poorly predicted by conventional numerical methods. Several canonical problems are investigated through large-scale numerical simulations to reveal the physical mechanism of forming local surface peak of heat flux. The main content of this study includes the following several aspects: 1) According to the characteristic of aerodynamic heating computation, to improve the accuracy and reliability of the prediction of heat flux, a high-order hybrid method and a compressible large eddy simulation method are developed by considering the stability of computing shock wave and the accuracy of boundary layer simulation. 2) The large-scale parallel computing for large eddy simulation is conducted for several canonical problems of shock wave/boundary layer interaction, and a reliable high-resolution database of instantaneous flow field is established for flow analyses. 3) Based on the numerical results, the evolution of the three-dimensional flow structure, the mechanism of the unsteady flow and the variation of the statistics of the turbulence are analysed to reveal the mechanism of forming the local transient heat flux.

本项目以高超声速飞行器气动防热应用为背景，针对激波/边界层干扰下常规的数值方法难以准确预测的局部瞬态高热流问题，发展高精度的数值计算方法，通过开展典型问题的大规模数值模拟与流动物理分析，揭示表面局部热流峰值形成的物理机制。主要研究内容包括：1) 根据气动热模拟的特点，发展兼顾激波计算稳定性与边界层模拟准确性的高阶混合通量格式与可压缩流动的大涡模拟方法，提高热流预测的准确性与可靠性； 2) 针对典型的激波/边界层干扰问题，开展大涡模拟大规模并行计算，建立可供流动分析的高分辨率瞬时流场数据库；3) 基于数值模拟结果深入开展流动物理分析，分别从壁面附近三维流动结构演化、边界层中粘性/无粘相互作用、流动非定常机制，以及激波干扰导致湍流特性变化等方面探讨局部瞬态高热流的形成机理。

针对高超声速飞行器激波-边界层干扰导致的局部瞬态高热流问题，发展相关数值模拟方法，通过开展典型构型的大规模数值计算与流动物理分析，揭示构型表面局部热流峰值形成的物理机制。具体研究内容包括：i) 根据高超声速气动热模拟的特点，发展相关数值计算方法，通过两个简单二维算例，验证了气动热预测的准确性与可靠性；ii) 选取典型的三维激波-边界层干扰问题，开展数值模拟大规模计算，分别从流动分离与再附、流动结构演化、表面热流分布和流动非定常机制等方面，探讨了激波-边界层干扰中局部瞬态高热流的形成机理。