FST方法分析二维Rayleigh-Bénard湍流热对流系统的能量输运

本文应用空间滤波方法：FST(Filter-space technique)方法，研究二维Rayleigh-Bénard(RB)湍流热对流系统中湍动能、热能和拟涡能的能量输运．研究中Rayleigh数(Ra)选取为1x10^8、1x10^9和1x10^10，Prandtl数(Pr)固定为4.38．我们展示了的结果表明，在二维RB系统中，三个Ra数下全场的平均湍动能和平均拟涡能在不同滤波尺度下的能量输运与Kraichnan在1967年预测的二维湍流中的级串理论有所偏差，而中心区域的能量都是向小尺度输运的．结果还揭示了瞬时能量输运的一些局部特性，包括它们在小尺度上不对称的分布．

Analyzing Energy and Enstrophy Transport in Two-Dimensional Rayleigh-Bénard Convection Based on Filter-Space Technique

We apply Filter-space technique (FST), to study the transport of kinetic energy, thermal energy, and enstrophy in two-dimensional Rayleigh-Bénard convection. In the study, the Rayleigh number was selected as 1x10^8, 1x10^9 and 1x10^10, and the Prandtl number was fixed at 4.38. Our results show that in two-dimensional Rayleigh-Bénard convection, cascades of the mean kinetic energy and the mean enstrophy are different from Kraichnan’s theory predicted in 1 967 when we choose different filter scales at all the three Rayleigh numbers, and the energy in the central region transfer from the large scale to the small scale. The results also show some local characteristic of the instantaneous energy transport, including their asymmetric distribution.