为了对低频液体表面波的频率和振幅进行测量,利用多普勒相干测速的工作原理,提出了一种液体表面散射激光与参考光相干涉的检测方法。对此进行了理论分析,得到了多普勒频移与液体表面波振幅之间的解析关系式,并利用贝塞尔函数分析了频谱分析图中解调出低频液体表面波频率的可行性,设计并实现了一套液体表面波多普勒相干检测的实验装置。结果表明,能够实时准确探测10Hz～40Hz的液体表面波参量,该方法为低频液体表面波的探测提供了新思路。

To measure the frequency and amplitude of low-frequency liquid surface wave,a detection method based on the principle of Doppler interferometry for velocity measurement is proposed,which makes use of interference between laser scattered on liquid surface and reference beams. Theoretical analysis was carried out to achieve the analytical expression for Doppler shift and amplitude of liquid surface wave.Also,the feasibility of demodulating frequency of low-frequency liquid surface wave from the spectrum was evaluated with Bessel functions.A test system was designed and implemented for Doppler interferometry for liquid surface wave. The test results show that parameters of liquid surface wave at 10Hz~40Hz can be measured accurately. This method provides a new solution for detection of liquid surface wave.