水面波作用下平面射流振翅运动的频率锁定现象

通过激光流动显示 (LIF)和测量方法 ,就表面水波对垂直平面射流的振翅运动的影响进行了实验和理论研究。研究表明 ,在表面波的影响下 ,振翅运动依然存在。同时 ,波高计和多谱勒激光测速仪的测量结果显示 ,当表面波的频率接近但低于射流振翅运动的自然频率时 ,射流振翅运动的实际振动频率将被锁定在表面波的频率上。而当表面波的频率大于射流振翅摆动的自然频率时 ,频率锁定现象将不存在。

FREQUENCY LOCK-IN PHENOMENON OF FLAPPING MOTION WITH SURFACE WATER WAVE

To study the effect of a progressive surface wave on the flapping motion of a vertical turbulent plane jet in shallow water, the laser visualizations and measurements were carried out in a water tank. The images of visualization by laser induced fluorescence (LIF) technique show that the jet flapping motion occurs in the wave environment. Using the wave height gauge and laser Doppler velocimetry (LDV), experimental results show that the jet flapping motions indeed lock in to the wave oscillations if the wave frequency is close to but lower than the nature frequency of jet flapping motion. The phenomenon does not occur when the wave frequency is above the nature frequency of jet flapping motion.