The "inactive" eddy motion and the large-scale turbulent pressure fluctuations in the dynamic sublayer
The "inactive" eddy motion and the large-scale turbulent pressure fluctuations in the dynamic sublayer
复制标题
DOI：
10.1175/1520-0469(1996)053
复制
发表时间：
1996-09
影响因子：
3.1
通讯作者：
G. Katul;J. Albertson;C. Hsieh;P. Conklin;J. Sigmon;M. Parlange;K. Knoerr
中科院分区：
文献类型：
--
作者：
G. Katul;J. Albertson;C. Hsieh;P. Conklin;J. Sigmon;M. Parlange;K. Knoerr
摘要利用自由空气静压探针测量了一大片森林草地动态子层中湍流压力脉动的统计结构，并采用汤森假设进行了模拟。汤森假设认为，平衡层中的涡旋运动可以分解为一个只与地面剪应力和高度有关的活动分量和一个由外部湍流产生的非活动分量。结果表明，当波数远小于地面高度时，非活跃涡运动对压力和纵向速度功率谱的贡献很大。由于这种不活跃的涡流运动的贡献的重要性，它是可能的，推导和验证的比例尺的压力功率谱在低波数。均方根压力来自地面剪应力使用简化的泊松方程，涉及到…
Abstract The statistical structure of the turbulent pressure fluctuations was measured in the dynamic sublayer of a large grass-covered forest clearing by a free air static pressure probe and modeled using Townsend's hypothesis. Townsend's hypothesis states that the eddy motion in the equilibrium layer can be decomposed into an active component, which is only a function of the ground shear stress and height, and an inactive component, which is produced by turbulence in the outer region. It is demonstrated that the inactive eddy motion contributes significantly to the pressure and longitudinal velocity power spectra for wavenumbers much smaller than that corresponding to the height above the ground surface. Because of the importance of this inactive eddy motion contribution, it was possible to derive and validate a scaling law for the pressure power spectrum at low wavenumbers. The root-mean-square pressure was derived from the ground shear stress using simplifications to the Poisson equation that relate t...