计算气动弹性若干研究进展

RECENT PROGRESS ON COMPUTATIONAL AEROELASTICITY

郭永怀和钱学森先生早在1946年提出了上临界马赫数的概念,即对于亚声速的二维无旋流动,当来流速度达到下临界马赫数时开始出现声速,稍增加来流速度,光滑无旋的亚、超声速混合流动可以继续存在,理论上只有当来流速度达到上临界马赫数出现激波后,光滑无旋流动才被破坏,随后,航空工程界先驱们为提高阻力发散马赫数,降低马赫数1附近的飞机阻力,为突破声障,提出了超临界翼型设计技术,引进了后掠翼设计概念,提出了跨声速面积律理论,导致了20世纪军民用航空飞行器的大规模发展,随着计算机技术和计算方法的进步,不同程度地简化流体控制方程的求解方法得到大发展,基于雷诺平均Navier-Stokes方程的计算流体力学已广泛应用于飞机性能评估、复杂流动机理分析。目前,气动外形优化设计、气动/结构耦合干扰、气动噪声等多学科问题成为空气动力学的研究热点,该文介绍作者的团队近年来在计算气动弹性研究方面的若干进展,作为对郭永怀先生诞辰100周年的怀念。

Corresponding to the lower critical Mach number, Kuo and Tsien proposed in 1946 the concept of upper critical Mach number. For two-dimensional irrotational flow on a body, before the maximum of local Mach number reaches a threshold, namely the upper critical Mach number, the irrotational supersonic flow still prevails, and only when the local Mach number exceeds the critical Mach number, the irrotational flow is eventually destroyed. Afterward, different design techniques of supercritical airfoils were developed to augment the drag-divergence Mach number, and the swept wings and area rule were introduced to overcome ＇sonic barrier＇ and to reduce the peak drag near Mach 1. These achievements brought about the tremendous development of aircraft industry in the last century. As the advancement of computer technique and computational method, the solution algorithms for different simplified governing equations of fluiddynamics were constructed. At present, computational fluid dynamics based the Reynolds averaged Navier-Stokes equation have been widely applied to the evaluation of aerodynamic performances and the understanding of complex flow mechanism. Aerodynamic optimization, fluid/structure interaction and aeroacousties et al have now become main research directions. To memorialize the 100 anniversary of Professor Guo Yung-Hual, recent studies on computational aeroelasticity by our research group were reviewed in the present paper.