Water surface capillary wave detection method based on optical devices
Studies of long-range propagation or detection of underwater sound waves mainly focus on scattering,re-flection,and transmission loss.Under these conditions,the water surface is often considered rigid such that the ti-ny capillary waves induced at the water-air interface are often neglected.In this study,water-air interface morphol-ogy is analyzed when an underwater far-field acoustic wave reaches the water surface.This water surface wave vi-brates at the nano level with the same frequency as the underwater incident sound wave,which decreases exponen-tially.Moreover,the maximum distance a water surface wave can travel decreases rapidly when its frequency in-creases.Based on the abovementioned discussion and the working principle of laser detection,a crossmedia under-water target detection system is designed,and a technical solution is provided to suppress interference from the low-frequency noise of ocean waves and reflections.Simulation reveals that this system has good resolution.Moreover,the devices used in this system are concealed,contactless,and easily maintained,having a good effect on the de-tection of low-frequency sound sources.By combining the advantages of a light wave traveling in air and a sound wave traveling in water,this method can be a new promising means for underwater target detection.