Phase-resolved flow field produced by a vibrating cantilever plate between two endplates
Phase-resolved flow field produced by a vibrating cantilever plate between two endplates
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DOI：
10.1063/1.1630796
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发表时间：
2004-01-01
影响因子：
4.6
通讯作者：
Chun, CH
中科院分区：
文献类型：
--
作者：
Kim, YH;Wereley, ST;Chun, CH
采用相位分辨粒子图像测速技术和烟雾可视化技术研究了振动悬臂板产生的流场。悬臂宽38毫米，长31毫米，由压电材料驱动。它浸泡在最初静止的空气中，即没有自由流速度施加在系统上。在这些实验中，悬臂梁的振动频率被设置为180赫兹，即悬臂梁的基本固有频率。流在本质上是相当复杂的。在每个振动周期中，会产生一对反向旋转的涡流。在这两个反向旋涡之间形成了一个高速区，其中最大速度几乎是板自由端最大速度的四倍。前后墙安装在悬臂的外侧边缘，最初的想法是使流动准二维。虽然在悬臂叶尖附近确实形成了二维流场，但叶尖下游的流动是复杂的、三维的。详细地获得了五种不同振幅的相分辨速度场。基于悬臂叶尖振动幅值和叶尖速度的雷诺数Re-h分别为146、126、101、72和43。在叶尖附近，无量纲化速度场几乎相同且对称，但在叶尖下游形成不对称流动，无量纲化速度场不再相同。应用振动可变形翼型的一般理论计算了各涡的随时间变化的环流，并与实验环流进行了比较。(C) 2004年美国物理研究所。
The flow field created by a vibrating cantilever plate was studied using phase-resolved particle image velocimetry measurements as well as a smoke visualization technique. The cantilever is 38 mm wide, 31 mm long, and is actuated by a piezoelectric material. It is immersed in initially quiescent air, i.e., no free stream velocity is imposed on the system. The cantilever's vibration frequency in these experiments is set to 180 Hz-the fundamental natural frequency of cantilever. The flow is quite complicated in nature. During each vibration cycle a pair of counter-rotating vortices is generated. A high velocity region is formed between these two counter-rotating vortices in which the maximum velocity is nearly four times the maximum speed of the free end of the plate. Front and rear walls are installed at the lateral edges of the cantilever initially with the thought of making the flow quasi-two-dimensional. While a two-dimensional flow field is indeed formed near the cantilever tip, the flow downstream of the tip is complex and three-dimensional. Phase-resolved velocity fields for five different amplitudes are acquired in detail. The corresponding Reynolds numbers Re-h based on the cantilever tip vibration amplitude and the tip speed are 146, 126, 101, 72, and 43, respectively. The nondimensionalized velocity fields are almost identical and symmetric near the tip, but asymmetric flows are formed and the nondimensionalized velocity fields are no longer identical further downstream of the tip. The time dependent circulation of each vortex is calculated by applying the general theory of oscillating, deformable airfoils and compared to the experimental circulation. (C) 2004 American Institute of Physics.