What are we learning from simulating wall turbulence?
What are we learning from simulating wall turbulence?
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DOI：
10.1098/rsta.2006.1943
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发表时间：
2007-03
期刊：
影响因子：
--
通讯作者：
J. Jiménez;R. Moser
中科院分区：
文献类型：
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作者：
J. Jiménez;R. Moser
近壁湍流的研究在过去十年中经历了复兴，这主要归功于高质量的数值模拟。光滑壁面上的粘性层和缓冲层基本上与外流无关，并且有一系列数值精确的非线性结构，它们约占能量产生和耗散的一半。其余的可以用它们的不稳定破裂来模拟。壁层的许多特征，如主要结构的尺寸，都可以通过这些模型很好地预测出来，这些模型基本上是在20世纪90年代完成的，因为计算机能力的提高使得20世纪80年代后期的运动学模拟变得足够便宜，可以进行动态实验。今天，我们正处于模拟对数（或重叠）层的早期阶段，有关其全局属性的许多细节正在变得清晰。例如，对数律的有限雷诺数修正已在湍流通道中得到验证。这使得重叠区域的上限和下限得到澄清，上限和下限都发生在离壁的距离比通常假设的要大得多的地方。在这部分气流中出现的各种叶栅的运动学图象也开始出现。预计在未来十年内可以实现动态理解。
The study of turbulence near walls has experienced a renaissance in the last decade, largely owing to the availability of high-quality numerical simulations. The viscous and buffer layers over smooth walls are essentially independent of the outer flow, and there is a family of numerically exact nonlinear structures that account for about half of the energy production and dissipation. The rest can be modelled by their unsteady bursting. Many characteristics of the wall layer, such as the dimensions of the dominant structures, are well predicted by those models, which were essentially completed in the 1990s after the increase in computer power made the kinematic simulations of the late 1980s cheap enough to undertake dynamic experiments. Today, we are at the early stages of simulating the logarithmic (or overlap) layer, and a number of details regarding its global properties are becoming clear. For instance, a finite Reynolds number correction to the logarithmic law has been validated in turbulent channels. This has allowed upper and lower limits of the overlap region to be clarified, with both upper and lower bounds occurring at much larger distances from the wall than commonly assumed. A kinematic picture of the various cascades present in this part of the flow is also beginning to emerge. Dynamical understanding can be expected in the next decade.