Distributed-Roughness-Induced Transient Growth in a Flat Plate Boundary Layer
Distributed-Roughness-Induced Transient Growth in a Flat Plate Boundary Layer
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平板边界层中分布粗糙度诱发的瞬态生长
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
E. White
中科院分区：
文献类型：
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作者：
M. Kuester;E. White
表面粗糙度以几种方式影响边界层转捩，包括作为瞬态生长的感受性机制。几个实验测量离散粗糙元素产生的瞬态增长，但是，很少有实验研究瞬态增长引起的分布表面粗糙度。在目前的工作中，瞬态增长所产生的随机分布，亚临界表面粗糙度沿流向扩展补丁测量在Blasius边界层。使用快速原型制造确定性粗糙表面，并使用热线风速仪进行粗糙度尾流的详细测量。分布的粗糙度在多个展向波长处产生扰动，这些扰动经历瞬态增长。这些实验奠定了基础工作检查的“屏蔽”效应，其中存在较小的振幅分布的粗糙度可能会降低强度的粗糙度尾流产生较大的粗糙度峰值。
Surface roughness affects boundary layer transition in several ways, including acting as a receptivity mechanism for transient growth. Several experiments have measured transient growth created by discrete roughness elements; however, very few experiments have studied transient growth initiated by distributed surface roughness. In the present work, transient growth created by streamwise-extended patches of randomly distributed, subcritical surface roughness is measured in a Blasius boundary layer. A deterministic roughness surface was manufactured using rapid prototyping, and detailed measurements of the roughness wake were made using hotwire anemometry. The distributed roughness creates disturbances at multiple spanwise wavelengths that undergo transient growth. These experiments lay the ground work for examining the “shielding” effect, wherein the presence of smaller amplitude distributed roughness may decrease the strength of roughness wakes created by larger roughness peaks.