Vortical structure and turbulence control in rotating fluids

首先描述了首席调查员获得的结果。已发表论文三篇。其中两篇论文是关于弯曲管道中的分岔现象，研究了与管道曲率相关的科里奥利力和离心力的竞争效应。结果表明，当这些影响达到平衡时，流量最大。另一个是关于旋转流体中的涡旋结构。在无平均剪切流的DNS中，发现共振相互作用在湍流二维化过程中起着重要作用。在平均剪切流的模拟中发现，当背景绝对涡度为零时，形成了相干结构。通过对紊流弯曲管道流动的实验研究，发现在管道入口注入旋流可以明显降低阻力，这将有助于工业应用。

First the results obtained by the head investigator are described. Three papers have been published. Two of them are on the bifurcation phenomena in the flow through a curved duct, where the competitive effect of the Coriolis force and the centrifugal force associated with the duct curvature is studied. It is found that when these effect are balanced, the flow flux is maximum. The other is on the vortical structure in the rotating fluids. In DNS without mean shear flow, it is found that the resonant interaction plays an important role in the two-dimensionalization process of turbulence. In the simulations with mean shear flow, it is found that a coherent structure develops when the background absolute vorticity is zero. Next the results obtained by the sub-investigator are described, By the experimental investigation of turbulent curved pipe flow, it is found that the injection of swirling flow at the inlet of the pipe reduces the drag appreciably, which will contribute industrial application.