Transitional Characteristics of Separated Shear Layer in the Vortex-Generating Region Behind a Body : Correspondence Between Image of Flow Visualization and Velocity Field Obtained by LDV Measurement at the Same Phase
Transitional Characteristics of Separated Shear Layer in the Vortex-Generating Region Behind a Body : Correspondence Between Image of Flow Visualization and Velocity Field Obtained by LDV Measurement at the Same Phase
复制标题
体后涡产生区分离剪切层的过渡特性:流动可视化图像与同相位LDV测量速度场的对应关系
DOI：
10.1299/kikaib.62.620
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Y. Obata
中科院分区：
文献类型：
--
作者：
H. Haniu;H. Sakamoto;M. Matsuda;Y. Obata
近年来，通过控制一小部分与钝体分离的剪切层来减小作用在钝体上的脉动流体力的研究已经开始。然而，分离的剪切层在涡产生区域的特性，这是关键信息，以确定一种有效的方式来控制流体力，还没有得到澄清。本研究利用流动显示之电脑影像处理，探讨在分离点附近的分离剪切层中所产生的小涡的下游行为。特别是，合并的阶段时，一个新的涡开始产生时，在阶段时的涡的增长是在中间阶段的小涡进行了详细的研究。同时，将激光多普勒测速仪测得的速度场与同一相位的可视化图像进行了比较，阐明了新涡产生的机理。
Recently, there have been some studies on reduction of fluctuating fluid forces acting on a bluffbody by controlling a small portion of the separated shear layer from the body. However, the characteristics of the separated shear layer in the vortex-generating region, which are key information to determine an effective way to control the fluid forces, have not been clarified yet. In this study, downstream behavior of small vortices generated in the separated shear layer near the separation point is investigated by computer image processing of flow visualization. In particular, coalescence of the small vortices at the phase when a new vortex is starting to generate and at the phase when the growth of the vortex is in the intermediate stage are investigated in detail. Also the velocity field mapped by LDV measurement is compared with the visualized image at the same phase to clarify the mechanism of the generation of new vortices.