Department of Mechanical Engineering, Yale University, New Haven, Connecticut 06520, USA.
Phys Rev Lett. 2010 Jun 25;104(25):254501. doi: 10.1103/PhysRevLett.104.254501. Epub 2010 Jun 21.
By studying the shape dynamics of three-particle clusters, we investigate the statistical geometry of a spatiotemporally chaotic experimental quasi-two-dimensional flow. We show that when shape and size are appropriately decoupled, these Lagrangian triangles assume statistically stationary shape distributions that depend on the flow scale, with smaller scales favoring more distorted triangles. These preferred shapes are not due to trapping by Eulerian flow structures. Since our flow does not have developed turbulent cascades, our results suggest that more careful work is required to understand the specific effects of turbulence on the advection of Lagrangian clusters.
通过研究三体团簇的形状动力学，我们研究了时空混沌实验准二维流的统计几何。我们表明，当形状和大小适当解耦时，这些拉格朗日三角形呈现出依赖于流尺度的统计稳定形状分布，较小的尺度有利于更扭曲的三角形。这些优先形状不是由于被欧拉流结构捕获所致。由于我们的流没有发展成湍流级联，我们的结果表明，需要更仔细地研究湍流对拉格朗日团簇输运的具体影响。
