Direct numerical simulations of turbulence with confinement and rotation
Direct numerical simulations of turbulence with confinement and rotation
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DOI：
10.1017/s0022112099005637
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发表时间：
1999-08
影响因子：
3.7
通讯作者：
F. Godeferd;L. Lollini
中科院分区：
文献类型：
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作者：
F. Godeferd;L. Lollini
这项工作的目的是分析固体旋转如何影响封闭在固体边界内的强迫湍流，并将其与Hopfinger等人（1982）进行的实验结果进行比较。为了确定与旋转，约束和强迫相关的各种机制，使用数值伪谱代码进行直接数值模拟。相对于实验的几何简化。首先，我们能够再现线性政权，作为传播的惯性波，经历反射的墙壁。第二，Ekman泵送现象，成比例的旋转速率，确定在自由衰减的湍流，其中由壁界定的流动的演变相比，无界均匀湍流的演变。最后，我们介绍了一个本地强迫在物理空间中的平面上，模拟的振荡网格的效果，使扩散湍流的创建，我们研究的结构下的流动的线性和非线性机制的组合。一个几乎是二维的状态的过渡示出之间发生的区域附近的强迫和外部区域中出现的旋涡，其数量取决于雷诺数和Rossby数。在这个区域中，湍流的各向异性进行了检查，并显示的数值预测再现许多最重要的功能存在于实验流。
The goal of this work is to analyse how solid body rotation affects forced turbulence enclosed within solid boundaries, and to compare it to results of the experiment performed by Hopfinger et al. (1982). In order to identify various mechanisms associated with rotation, confinement, and forcing, a numerical pseudo-spectral code is used for performing direct numerical simulations. The geometry is simplified with respect to the experimental one. First, we are able to reproduce the linear regime, as propagating inertial waves that undergo reflections at the walls. Second, the Ekman pumping phenomenon, proportional to the rotation rate, is identified in freely decaying turbulence, for which the evolution of the flow bounded by walls is compared to the evolution of unbounded homogeneous turbulence. Finally we introduce a local forcing on a plane in physical space, for simulating the effect of an oscillating grid, so that diffusive turbulence is created, and we examine the structuring of the flow under the combination of the linear and nonlinear mechanisms. A transition to an almost two-dimensional state is shown to occur between the region close to the forcing and an outer region in which vortices appear, the number of which depends on the Reynolds and Rossby numbers. In this region, the anisotropy of turbulence is examined, and the numerical predictions are shown to reproduce many of the most important features present in the experimental flow.