IUTAM Symposium on Unsteady Separated Flows and their Control
IUTAM Symposium on Unsteady Separated Flows and their Control
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IUTAM 非定常分离流及其控制研讨会
DOI：
10.1007/978-1-4020-9898-7_47
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Jukes T
中科院分区：
文献类型：
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作者：
Jukes T
采用高速粒子图像测速技术，研究了在Re = 6500时控制圆柱近尾迹流场的可能性。表面等离子体致动器安装在圆柱体周围的关键位置（分离点的前后），并通过产生靠近壁面的体力来控制流量。研究发现，等离子体可以显著改变圆柱体尾迹中的涡流脱落，其效果取决于执行器的位置和强制频率。当等离子体非常接近自然层流分离点时，观察到最显著的效应。在这里，当等离子体以自然涡脱落频率（Stf≈0.2;StK= 0.206）激发时，可以观察到脱落的放大。这是伴随着周期性的流动再附着到至少后滞止点。在较高的强迫频率下（Stf≥0.8），等离子体完全抑制了涡脱落过程，使尾迹变短变窄，湍流强度减小，尾迹动量厚度减小60%。在更高频率下（Stf≥2.0,StSL= 1.7），只有剪切层被激发，涡街保持不变。
An experimental investigation has been undertaken using high-speed Particle Image Velocimetry to study the possibility of controlling the global flow field in the near wake of a circular cylinder at Re = 6,500.Surface plasma actuators were mounted at strategic locations around the cylinder (both fore and aft of the separation point) and used for flow control by producing a body force close to the wall.It was found that the plasma can significantly alter the vortex shedding in the wake of the cylinder, with effectiveness depending upon the actuator location and forcing frequency.The most dramatic effects were observed when the plasma was located very close to the natural laminar separation point.Here, amplification of the shedding was observed when the plasma was excited at the natural vortex shedding frequency (Stf≈ 0.2; StK= 0.206).This was accompanied by periodic flow reattachment to at least the rearward stagnation point.At higher forcing frequency (Stf≥ 0.8), the plasma completely suppressed the vortex shedding process which lead to a short and narrow wake, reduced turbulence intensity, and 60% reduction in the wake momentum thickness.At still higher frequency (Stf≥ 2.0; StSL= 1.7), only the shear layers were excited and the vortex street remained unaltered.