Local shear stress measurements on an axisymmetric body in a microbubble modified flow field
Local shear stress measurements on an axisymmetric body in a microbubble modified flow field
复制标题
微泡修正流场中轴对称体的局部剪切应力测量
DOI：
10.1063/1.857800
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发表时间：
1990
影响因子：
4.6
通讯作者：
S. Pal
中科院分区：
文献类型：
--
作者：
S. Deutsch;S. Pal
一组齐平安装的热膜探针已被用于测量在四个离散的自由流速度为4.6，10.7，13.2和16.8 m/sec的轴对称体上微泡注射导致的局部剪切应力降低。气泡流型的可视化在中间自由流速度下补充了这些结果。在速度为10.7 m/sec及以上时，在喷射下游一定距离处出现表面摩擦的周向梯度，模型顶部的表面摩擦减小大于底部。对于这些速度，梯度在较低速度和较高气体注入条件下更强。较高的速度倾向于驱动梯度的轴向位置远离注射位置。在低于10.7米/秒的速度下，流动由双涡结构主导，双涡结构夹带模型底部和侧面的气泡并将其输送到顶部。在足够高的气体流速下，一个足够大的肉眼可见的空腔形成在…
An array of flush‐mounted hot film probes has been used to measure the local shear stress reduction as a result of microbubble injection over an axisymmetric body at the four discrete, free‐stream speeds of 4.6, 10.7, 13.2, and 16.8 m/sec. Visualization of the bubble flow pattern supplement these results at intermediate free‐stream speeds. At speeds of 10.7 m/sec and above, a circumferential gradient in skin friction, with skin friction reduction larger at the top than at the bottom of the model occurs at some distance downstream of injection. For these speeds, the gradient is stronger at the lower speeds and higher gas injection conditions. Higher speeds tend to drive the axial location of the gradient farther from the injection location. At speeds below 10.7 m/sec, the flow is dominated by a double vortex structure that entrains the bubbles at the bottom and sides of the model and transports them to the top. At sufficiently high gas flow rates a cavity, large enough to be observed visually, is formed ju...