Linear and nonlinear stability of plane stagnation flow
Linear and nonlinear stability of plane stagnation flow
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平面停滞流的线性和非线性稳定性
DOI：
10.1017/s0022112085002944
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发表时间：
1985
影响因子：
3.7
通讯作者：
P. Huerre
中科院分区：
文献类型：
--
作者：
By M. J. Lyell;P. Huerre
平面滞止流对三维扰动是线性稳定的。这项理论研究的目的是表明，同样的流量可以不稳定，如果波动水平足够高。在本公式中，有限振幅扰动扩展的本征函数有关的线性稳定性的潜在的停滞流和Galerkin方法是用来推导耦合不同模式的非线性振幅方程。基于线性理论的最小阻尼本征函数的两模和三模相互作用模型表明，三维波动可以被触发以指数方式增长到一定的临界强度以上。这种阈值的存在与钝体绕流中产生的二次涡的实验研究定性一致。
Plane stagnation flow is known to be linearly stable to three-dimensional perturbations. The purpose of this theoretical study is to show that the same flow can be destabilized if fluctuation levels are sufficiently high. In the present formulation, finite-amplitude disturbances are expanded in terms of the eigenfunctions pertaining to the linear stability of potential stagnation flow and a Galerkin method is used to derive the nonlinear amplitude equations coupling the different modes. Two- and three-mode interaction models based on the least-damped eigenfunctions of linear theory indicate that three-dimensional fluctuations can be triggered to grow exponentially above a certain critical intensity. The existence of such a threshold is in qualitative agreement with experimental studies of the secondary vortices arising in flows past blunt bodies.