Alignment Trends of Velocity Gradients and Subgrid-Scale Fluxes in the Turbulent Atmospheric Boundary Layer
Alignment Trends of Velocity Gradients and Subgrid-Scale Fluxes in the Turbulent Atmospheric Boundary Layer
复制标题
湍流大气边界层中速度梯度和亚网格尺度通量的对齐趋势
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
C. Meneveau
中科院分区：
文献类型：
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作者：
C. Higgins;M. Parlange;C. Meneveau
使用统计几何工具分析大气表层的现场实验数据。数据由声速计阵列的速度测量值组成。在大涡模拟 (LES) 的背景下，这些阵列允许进行区分大尺度和小尺度所需的空间过滤。根据数据评估与 LES 相关的各种量的时间序列。结果表明，首选的过滤流体变形是轴对称延伸，首选的亚网格应力状态是轴对称收缩。过滤后的脉动涡度显示出与平均涡度、流向以及中间应变率特征向量的优选对准。亚网格尺度应力的特征向量和过滤应变率之间的对齐用于测试涡流粘度和混合模型公式。与先前在低得多的雷诺数下的实验室测量结果定性一致，观察到双峰分布，可以使用混合模型将其简化为与涡流粘度闭合良好对齐。
Field experimental data in the atmospheric surface layer are analyzed using toolsfrom statistical geometry. The data consist of velocity measurements from sonicanemometer arrays. In the context of large eddy simulations (LES), these arrayspermit the spatial filtering needed to separate large from small scales. Time seriesof various quantities relevant to LES are evaluated from the data. Results show thatthe preferred filtered fluid deformation is axisymmetric extension and the preferredsubgrid stress state is axisymmetric contraction. The filtered fluctuating vorticityshows preferred alignments with the mean vorticity, with the streamwise direction,and with the intermediate strain-rate eigenvector. The alignment between eigenvectorsof the subgrid-scale stress and filtered strain rate is used to test eddy viscosity andmixed model formulations. In qualitative agreement with prior laboratory measurements at much lower Reynolds numbers, a bimodal distribution is observed, which can be reduced to good alignment with eddy viscosity closure using the mixed model.