Numerical simulation for rarefied hypersonic flows over non-rectangular deep cavities
Numerical simulation for rarefied hypersonic flows over non-rectangular deep cavities
复制标题
非矩形深腔稀薄高超声速流数值模拟
DOI：
10.1063/5.0102685
复制
发表时间：
2022-07
影响因子：
4.6
通讯作者：
Bing Wang
中科院分区：
文献类型：
--
作者：
Xuhong Jin;Xiaoli Cheng;Qiang Wang;Bing Wang
采用直接模拟Monte Carlo方法，对稀薄高超声速绕流各种非矩形空腔构型进行了全面的数值研究，深入分析了自由流马赫数、高温气体效应和三维效应的影响。在这项工作中，考虑了两组非矩形腔：一个是浅前型，另一个是浅后型。主要目的是获得洞察这些非矩形腔的流动特性和表面压力和热通量。使空腔的前部或后部变浅不会过多地改变上部空腔内的流动特性，但会导致涡流不再充满整个空腔。相反，在底部空腔中形成“死水”区域，并且该“死水”区域随着空腔的前部或后部变浅而扩大。此外，凹腔前部或后部变浅对凹腔后壁面压力和热流密度的影响不大，但对凹腔底部表面压力和换热系数的分布有重要影响。对于后腔较浅的情况，腔底右端的表面压力和热流密度分别是矩形腔的2倍和20倍。自由流马赫数和高温气体效应对空腔内流动特性的影响很小，可以忽略不计，而三维效应起着重要的作用。与2D空腔相比，有限跨度空腔中的3D缓解效应防止外部流更深地渗透到空腔中，导致空腔地板上的表面压力和热通量小得多。
A comprehensive numerical study is performed to investigate rarefied hypersonic flows past various non-rectangular cavity configurations using the direct simulation Monte Carlo method with the effects of free-stream Mach numbers, high-temperature gas effects, and three-dimensional (3D) effects analyzed in depth. In this work, two groups of non-rectangular cavities are considered: one is the shallow-front type and the other is the shallow-rear type. The primary objective is to obtain insight into the flow characteristics and surface pressure on and heat flux to these non-rectangular cavities. Making the front or rear of the cavity shallower does not alter the flow characteristics inside the upper cavity too much, but it causes the vortex to not fill the entire cavity any longer. Instead, a “dead-water” region is formed in the bottom cavity, and this “dead-water” region becomes expanded as the front or rear of the cavity gets shallower. In addition, making the front or rear of the cavity shallower has little influence on surface pressure on and heat flux to the aft wall of the cavity, while it plays an important role in the distributions of surface pressure and heat transfer coefficients over the cavity floor. For the case of shallower-rear cavity, the surface pressure and heat flux at the right end of the cavity floor are as high as 2 and 20 times the rectangular-cavity value, respectively. Free-stream Mach number and high-temperature gas effects have a negligibly minor influence on flow characteristics inside the cavity, while 3D effects play an important role. In comparison with 2D cavities, 3D relieving effects in finite-span cavities prevent the external stream from penetrating deeper into cavities, leading to much smaller surface pressures on and heat fluxes to the cavity floors.