Effects of large-scale free stream turbulence on a turbulent boundary layer
Effects of large-scale free stream turbulence on a turbulent boundary layer
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大规模自由流湍流对湍流边界层的影响
DOI：
10.1063/1.3225146
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发表时间：
2009
影响因子：
4.6
通讯作者：
Z. Warhaft
中科院分区：
文献类型：
--
作者：
N. Sharp;S. Neuscamman;Z. Warhaft
给出了平板边界层上自由流湍流有系统变化的风洞实验结果。在板块的上游，一个活跃的网格产生了强度从0.25%到10.5%的自由流动湍流。边界层的动量厚度雷诺数从550变化到近3000。在所有情况下，自由流湍流长度尺度与边界层深度的比率都大于1。Hotwire测量表明，在高湍流强度下，自由流湍流的影响深入边界层，影响壁面应力和小尺度(导数)统计量。预乘后的能谱呈双峰型。在很低的自由流湍流强度下，这些峰值与湍流边界层的内外尺度有关，但在高湍流强度时，自由流能量峰主导着边界层的外部尺度。这件事的影响……
Results of a wind tunnel experiment in which there are systematic variations of free stream turbulence above a flat-plate boundary layer are presented. Upstream of the plate, an active grid generates free stream turbulence varying in intensity from 0.25% to 10.5%. The momentum thickness Reynolds number of the boundary layer varies from 550 to nearly 3000. In all cases, the ratio of the free stream turbulence length scale to the boundary layer depth is greater than unity. Hotwire measurements show that, at high turbulence intensities, the effects of the free stream turbulence extend deep into the boundary layer, affecting the wall stress as well as the small-scale (derivative) statistics. Premultiplied energy spectra show a double peak. At very low free stream turbulence intensities these peaks are associated with the inner and outer scales of the turbulent boundary layer, but at high turbulence intensities the free stream energy peak dominates over the boundary layer’s outer scale. The implications of the...