激波反射问题精细结构研究

Theoretical models will be constructed to describe and predict the shock reflection structure, especially the Mach reflection structure, for supersonic flow shock reflection problems more complex than before. . Both shock dynamics theories and computational fluid dynamics (CFD) simulations will be used as preliminary tools to conduct the studies of four specific problems: (1) the fine structure of the flow field for Mach reflection wave, (2) theoretical model for asymmetric shock wave reflection theory, (3) theoretical model for viscous effect on shock wave reflection, and (4) shock reflection theory for multiple incident shock waves.. Finding the critical condition for transition of multi-shock wave reflection patterns and building theoretical models for predicting Mach reflection structure accounting for more complex factors than before constitute the key difficulties to be resolved in this study. . The purpose of this study is to treat problems more closely related to application requirement, accounting for the importance of more effects besides the inflow Mach number and wedge deflection angle.. By this study, the importance of secondary flow structures in Mach reflection will be understood in more detail than before, the influence on shock reflection by additional factors such as viscosity, asymmetry of geometry and perturbation such as a second incident shock wave, which have not been considered before in theoretical studies, will be made clear. . The present study extends the range of study of shock reflection problems. It is meaningful in improving the depth of the study of shock reflection theory and making the theory of shock reflection more close to engineering practice.

针对超声速流动激波反射问题，用激波动力学理论构建复杂条件下的理论模型，用以描述和预测激波反射结构，尤其是马赫反射结构。采用激波动力学理论分析和CFD等研究手段，完成马赫反射流场波系结构精细刻画研究，完成非对称激波相交或反射理论模型研究，完成激波反射粘性修正理论研究，完成多激波反射规律研究。拟解决多激波反射临界条件的建立和复杂条件下激波反射波系结构形状的预测等关键科学问题。研究目标是，获得来流马赫数和楔角以外的一些因素对激波反射规律的影响。通过四项内容的研究，在过去对激波反射大尺度结构重要性认识的基础上，获得激波反射中二次波系结构的形态，得到粘性效应、几何非对称效应以及尖楔二次偏转对激波反射的影响规律。这些研究拓展了现有激波反射研究的范围，对提高激波反射理论研究的深度和让激波反射理论成果更贴近工程实际均有重要意义。

本项目中，针对二维定常超声速流动中的马赫反射问题，以前期的马赫反射理论模型作为基础，基于对流场精细结构的深入理解，针对考虑粘性的马赫反射问题、多激波马赫反射问题和非对称马赫反射问题进行了研究。.研究采用理论建模分析方法，并采用CFD数值模拟结果对理论模型进行验证。提出并验证了马赫反射的粘性效应修正方法，得到等效楔角、等效楔尾高度表达式，并解释了粘性的影响机理。提出并验证了双激波马赫反射的理论模型，针对双激波马赫反射中的前马赫反射给出了第二道入射激波和反射激波相交产生第I类和第II类干扰的临界条件。提出并验证了非对称马赫反射理论模型，发现马赫杆高度强烈依赖于楔角的不对称性、而近似线性地依赖于楔下表面长度的不对称性。.以上研究结果可以拓宽现有激波反射研究的范围，对提高激波反射理论研究的深度和让激波反射理论成果更贴近工程实际均有重要意义。