Steady and Unsteady Boundary-Layer Separation
Steady and Unsteady Boundary-Layer Separation
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稳态和非稳态边界层分离
DOI：
10.1146/annurev.fl.18.010186.001213
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发表时间：
1986
影响因子：
27.7
通讯作者：
F. Smith
中科院分区：
文献类型：
--
作者：
F. Smith
Brown和Stewartson（1969）对火焰流分离的回顾是这样开始的：“分离现象是不可压缩流体在高雷诺数下通过无压体运动的最有趣的特征之一。在这里，到目前为止一直与物体密切接触的主流，突然，没有明显的原因，脱离了，下游形成了一个漩涡流区域，即使其他地方的流动是层流，通常也是湍流的。”这些开头的几句话——紧随其后的是上述作者精彩而及时的论述，强调了与经典边界层分离相关的困难——为本篇关于当前技术状况的文章提供了一个恰当的开端。Brown & stewart实际上强烈暗示的主要特征是，考虑到经典理论在分离时的失败（由于S. Goldstein（1948）类型的奇点），一个新的非经典开始对于高雷诺数理论包含分离流是必要的。这一开端是由Stewartson & Williams（1969）、Neiland（1969）和Messiter（1970）提出的。我们的目标是从1969年以来取得的重大进展，到最近的发展，以及在不久的将来，“稳定和不稳定分离的理性理论”可能取得进展的领域。从大特征雷诺数Re下流动结构的研究中得到的物理和理论认识是有价值的。主要有三个方面，即与实验和数值结果的比较，为研究提供了依据
The inspiring review oflaminar separation by Brown & Stewartson (1969) begins thus: "The phenomenon of separation is one of the most interesting features of the motion of an incompressible fluid past a bluff body at high Reynolds number. Here the main stream, which has hitherto been in close contact with the body, suddenly, and for no obvious reason, breaks away, and downstream a region of eddying flow, which is usually turbulent even if the flow elsewhere is laminar, is set up." These opening lines-which were followed by the above authors' brilliant and timely discourse emphasizing the difficulties associated with separation in classical boundary layers make an apt beginning for the present article on the current state of the art. The main feature, to which Brown & Stewarts on in fact alluded strongly, is that given the failure [due to singularities of the S. Goldstein (1948) type] in classical theory at separation, a fresh nonclassical start is necessary for high-Reynolds-number theory to encompass separating flow. This start was made by Stewartson & Williams (1969), Neiland (1969), and Messiter (1970). Our aim is to go from the significant advances made since 1969 to the recent developments and the possible areas of progress in the near future for the rational theory 'of steady and unsteady separation. The physical and theoretical understanding that can emerge from the study of flow structures at large characteristic Reynolds numbers Re is valuable for many reasons. Three major ones are the helpful comparisons with experiments and numerical results, the foundation such study gives to