Theoretical model for the separated flow around an accelerating flat plate using time-dependent self-similarity
Theoretical model for the separated flow around an accelerating flat plate using time-dependent self-similarity
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DOI：
10.1103/physrevfluids.6.054701
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发表时间：
2021-05-10
影响因子：
2.7
通讯作者：
Mohseni, K.
中科院分区：
文献类型：
--
作者：
DeVoria, A. C.;Mohseni, K.
我们提出了一个适合于平板翼型在无粘流体中加速初始运动的模型。该模型基于Pullin和Wang [J. Fluid Mech.509，1（2004）]中提出的模型，旨在将有效性范围扩展到较低的攻角和较长的行进距离。分离流结构以常规方式表示为涡面，并发展了适用于平板前缘和后缘的局部相似展开式。在我们的方法中，一个扩展被应用到附加的外部流动，而不是涡面环流和位置。这使得平行于平板的自由流的扫掠分量的不对称效应可以建立在与单阶流相同的控制方程中。此外，我们开发了一个随时间变化的自相似过程，允许更复杂的流动结构的演变建模。这是通过相似性变量的隐式时间变化来实现的。作为一个集体的结果，预测的涡动力学和力量的板比较有利的Navier-Stokes模拟。该模型分为高和低攻角制度。前者假设前缘流和后缘流独立演化，而后者则进一步简化以耦合两种流。
We present a model appropriate to the initial motion of a flat-plate airfoil accelerating in an inviscid fluid. The model is based on the one presented in Pullin and Wang [J. Fluid Mech. 509, 1 (2004)] and is intended to extend the range of validity to lower angles of attack and longer distances traveled. The separated flow structures are represented as vortex sheets in the conventional manner and similarity expansions locally applicable to the leading and trailing edges of the plate are developed. In our approach, an expansion is applied to the attached outer flow rather than the vortex sheet circulations and positions. This allows the asymmetric effect of the sweeping component of the free-stream flow parallel to the plate to be built in to the same governing equation as the singular-order flow. Additionally, we develop a time-dependent self-similarity procedure that allows the modeling of more complex evolution of the flow structures. This is accomplished through an implicit time variation of the similarity variables. As a collective result, the predicted vortex dynamics and forces on the plate compare favorably to Navier-Stokes simulations. The model is split into high and low angles of attack regimes. The former assumes that the leading-edge and trailing-edge flows evolve independently, while the latter makes a further simplification to couple the two flows.