Drag reduction of flexible plates by reconfiguration
Drag reduction of flexible plates by reconfiguration
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DOI：
10.1017/s0022112009993673
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发表时间：
2010-05-10
影响因子：
3.7
通讯作者：
Machado-Almeida, Bruno A.
中科院分区：
文献类型：
--
作者：
Gosselin, Frederick;de Langre, Emmanuel;Machado-Almeida, Bruno A.
通过两种几何形状的柔性板在空气中的广泛和系统的实验研究，它表明，一个适当定义的缩放柯西数允许崩溃的重构数的所有阻力测量。在渐近制度的大变形，它表明，Vogel指数，缩放阻力与流速为不同的几何形状的板可以预测一个简单的量纲分析推理。这些预测的Vogel指数与先前公布的模型的重新配置。负责重新配置，即面积减少和精简，机制进行了研究，与一个简单的模型的基础上的经验阻力配方的柔性板的帮助。该模型很好地预测了实验中观察到的重构，并表明，对于一个矩形板，流线化的效果是突出的重构开始时，但面积减少占主导地位的政权的大变形。此外，该模型表明，对于两种几何形状的板的重构不能描述由一个单一的值的Vogel指数。Vogel指数渐近地接近小的和非常大的尺度柯西数的常数值，但在两个极端之间，它在很大的尺度柯西数范围内变化显着。
Through an extensive and systematic experimental investigation of two geometries of flexible plates in air, it is shown that a properly defined scaled Cauchy number allows collapsing all drag measurements of the reconfiguration number. In the asymptotic regime of large deformation, it is shown that the Vogel exponents that scale the drag with the flow velocity for different geometries of plates can be predicted with a simple dimensional analysis reasoning. These predicted Vogel exponents are in agreement with previously published models of reconfiguration. The mechanisms responsible for reconfiguration, namely area reduction and streamlining, are studied with the help of a simple model for flexible plates based on an empirical drag formulation. The model predicts well the reconfiguration observed in the experiments and shows that for a rectangular plate, the effect of streamlining is prominent at the onset of reconfiguration, but area reduction dominates in the regime of large deformation. Additionally, the model demonstrates for both geometries of plates that the reconfiguration cannot be described by a single value of the Vogel exponent. The Vogel exponent asymptotically approaches constant values for small and for very large scaled Cauchy numbers, but in between both extremes it varies significantly over a large range of scaled Cauchy number.