湍流发生机制的新发现

turbulencest

Eliminating Turbulence in Spatially Intermittent Flows
http://www.sciencemag.org/cgi/content/abstract/sci;327/5972/1491

Björn Hof,1,* Alberto de Lozar,1 Marc Avila,1 Xiaoyun Tu,1,{dagger} Tobias M. Schneider2

Flows through pipes and channels are the most common means to transport fluids in practical applications and equally occur in numerous natural systems. In general, the transfer of fluids is energetically far more efficient if the motion is smooth and laminar because the friction losses are lower. However, even at moderate velocities pipe and channel flows are sensitive to minute disturbances, and in practice most flows are turbulent. Investigating the motion and spatial distribution of vortices, we uncovered an amplification mechanism that constantly feeds energy from the mean shear into turbulent eddies. At intermediate flow rates, a simple control mechanism suffices to intercept this energy transfer by reducing inflection points in the velocity profile. When activated, an immediate collapse of turbulence is observed, and the flow relaminarizes.

1 Max Planck Institute for Dynamics and Self-Organisation, Bunsenstrasse 10, 37073 Göttingen, Germany.
2 School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138, USA.

{dagger} Present address: LaVision GmbH, 37081 Göttingen, Germany.

* To whom correspondence should be addressed. E-mail: bhof@gwdg.de

周华

支持新发现！

周华

最好有关于新机制的详细介绍。

ytuym

最好能有湍流新机制的详细介绍，最好附带文献，可以下载。

turbulencest

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SKLCC虫草晶

湍流的猝发机制始终都是一个非常有趣&非常关键的难点！
最近两年在JFM和Phys. Fluids上面也连续出现了几篇相关的工作。随着计算机（大规模集群）硬件性能的快速提升，这方面的研究应该又会“热起来”，期待新的结果（单相&两相）。