论文标题
研究壁湍流中的非线性：再生与参数机制
Investigating nonlinearity in wall turbulence: regenerative versus parametric mechanisms
论文作者
论文摘要
两种线性生长过程与波动之间的平均流量和非线性相互作用转移的非正态性相关，有助于维持湍流。但是，缺乏对维持动荡状态的合作机制的详细理解。在本报告中，我们通过改变COUETTE流动湍流动力学中相关项的大小来确定这种非线性成分如何帮助维持和确定湍流状态的结构，尤其是该机制是参数或再生的，从而研究了波动 - 透明非线性的作用。确定支持Navier-Stokes湍流中波动场的机制是参数，然后我们研究了通过使用时间依赖性分辨率分析来检查频率域中的参数平均生长，通过参数依赖性平均流中的参数均值流中的参数均值生长来维持湍流的波动成分。
Both linear growth processes associated with non-normality of the mean flow and nonlinear interaction transferring energy among fluctuations contribute to maintaining turbulence. However, a detailed understanding of the mechanism by which they cooperate in sustaining the turbulent state is lacking. In this report, we examine the role of fluctuation-fluctuation nonlinearity by varying the magnitude of the associated term in the dynamics of Couette flow turbulence to determine how this nonlinear component helps maintain and determine the structure of the turbulent state, and particularly whether this mechanism is parametric or regenerative. Having determined that the mechanism supporting the fluctuation field in Navier-Stokes turbulence is parametric, we then study the mechanism by which the fluctuation component of turbulence is maintained by parametric growth in a time-dependent mean flow by examining the parametric growth mechanism in the frequency domain using analysis of the time-dependent resolvent.
