An experimental study on characteristics of turbulence generated by oscillating grids in a wave tank
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摘要: 在波浪水槽中采用格栅振动的方式产生湍流,研究振动格栅产生湍流的特征。本文开展了4类实验,调节测量点到格栅平均位置的距离、格栅振动频率、振动冲程,采用ADV测量水体中单点的脉动速度。实验结果显示,湍流强度在一定范围内随离格栅距离的增大而逐渐减小,随着振动频率的增大而呈幂指数增大,随着振动冲程的增大而呈幂指数增大。同时还比较了两个不同格栅产生湍流的不同。结果显示,在波浪水槽中,振动格栅产生湍流的强度还与格栅的长度尺寸有关,这与在水箱中振动格栅产生湍流的特征不同。Abstract: In this paper, we study the characteristics of turbulence generated by oscillating grids in a wave tank. Four experiments are carried out. High-frequency velocity fluctuations with different depths of measurement points, vibration frequency, vibration stroke were recorded by an acoustic Doppler velocimeter (ADV). The experiments results show that, the turbulence strength becomes weak with increasing the distance from measurement points to grid position, becomes strong with increasing vibration frequency and vibration stoke respectively as power function. At the meantime, the turbulence strength of two different grids was compared. From the results we know that the length of grid has great influence on turbulence strength, this is different from the turbulence characteristic in a water box.
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Key words:
- wave tank /
- oscillating grid /
- turbulence
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