Open-Loop Control of Disk Wakes
Open-Loop Control of Disk Wakes
复制标题
磁盘唤醒的开环控制
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
Joseph W. Hall
中科院分区：
文献类型：
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作者：
R. Bigger;H. Higuchi;Joseph W. Hall
基于分别为 67,000 和 20,000 的圆盘直径，使用雷诺数的粒子图像测速技术研究了亚音速气流和水流中圆盘近尾流的开环控制。空气模型的边缘有由电磁执行器径向驱动的凸片，水模型的槽连接到流体外部的活塞和气缸。在这两个系统中，驱动频率可以改变，并且在空气中，可以控制强迫的空间范围。对称驱动使空气和水的再循环区域长度减少了 10%。此外，空气中基本自然涡旋脱落频率的螺旋激励导致频率降低 15%，并导致尾流与激励同相强烈振荡。最有效的对称驱动频率对应于非受迫尾流中非对称模式固有频率的两倍。详细介绍并讨论了驱动对瞬时速度场和平均速度场的影响。
Open-loop control in the near wake of a disk in subsonic air and water flows was investigated using particle image velocimetry at a Reynolds number based on the disk diameters of 67,000 and 20,000, respectively. The air model had tabs along the edge that were driven radially by electromagnetic actuators, and the water model had slots connected to a piston and cylinder external to the flow. In both systems, the frequency of actuation could be varied, and in air, the spatial extent of the forcing could be controlled. Symmetrical actuation produced a reduction in the recirculation-region length of 10% for both air and water. Additionally, a helical excitation at the fundamental natural vortex-shedding frequency in air caused a reduction of 15 % and caused the wake to oscillate strongly in phase with the excitation. The most effective symmetrical actuation frequencies correspond to twice the natural frequency of the asymmetric mode in the unforced wake. The effects of actuation on the instantaneous and mean velocity fields are presented and discussed in detail.