Parameterizing interaction of disparate scales: Selective decay by Casimir dissipation in fluids
Parameterizing interaction of disparate scales: Selective decay by Casimir dissipation in fluids
复制标题
不同尺度的参数化相互作用：流体中卡西米尔耗散的选择性衰变
DOI：
--
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Darryl D. Holm
中科院分区：
文献类型：
--
作者：
F.Gay;Darryl D. Holm
通过考虑二维不可压缩湍流的性质，解决了流体流动中不同尺度相互作用的参数化问题。我们考虑的性质是选择性衰减，其中理想公式的卡西米尔（二维流中的熵）随时间衰减，而能量基本保持恒定。本文介绍了流体动力学中通过强制卡西米尔耗散产生选择性衰减的机制。在某些情况下，这种机制与引用{SaBa1981，SaBa1985}中讨论的预期涡度数值方法有关。给出了几个例子，并利用理想理论的李泊松结构发展了选择性衰变的一般理论。尺度选择算子允许流体运动方程的最终修改在几个例子中被解释为参数化不同尺度之间的非线性动态相互作用。这里导出的修正流体方程系统的类型可能在湍流地球物理流动中有用，在湍流地球物理流动中，依赖于实际粘度的较慢的间接影响在计算上是禁止的，例如在与小得多的涡流相互作用的大规模，连贯的海洋流动中。
The problem of parameterizing the interactions of disparate scales in fluid flows is addressed by considering a property of two-dimensional incompressible turbulence. The property we consider is selective decay, in which a Casimir of the ideal formulation (enstrophy in 2D flows) decays in time, while the energy stays essentially constant. This paper introduces a mechanism that produces selective decay by enforcing Casimir dissipation in fluid dynamics. This mechanism turns out to be related in certain cases to the numerical method of anticipated vorticity discussed in cite{SaBa1981,SaBa1985}. Several examples are given and a general theory of selective decay is developed that uses the Lie-Poisson structure of the ideal theory. A scale-selection operator allows the resulting modifications of the fluid motion equations to be interpreted in several examples as parameterizing the nonlinear, dynamical interactions between disparate scales. The type of modified fluid equation systems derived here may be useful in turbulent geophysical flows where it is computationally prohibitive to rely on the slower, indirect effects of a realistic viscosity, such as in large-scale, coherent, oceanic flows interacting with much smaller eddies.
影响因子：
3.2
作者：
H. Weller
通讯作者：
H. Weller