The influence of high frequency ultrasonic waves on the bubble wake features of underwater vehicles is experimentally studied. The experimental results show that under the action of the high frequency ultrasonic wave, the bubble wake feature intensity of the underwater vehicle is weakened and the duration is shortened. Under the same intensity, the degree of attenuation of the bubble wake features is different under the action of different frequency ultrasonic waves. Among them, 1.2 MHz ultrasonic waves have the best inhibitory on the bubble wake. Under the same frequency, as the intensity increases, the inhibitory effect of the ultrasonic wave on the bubble wake is enhanced.
During the navigation of the underwater vehicle(mainly refers to the manned underwater vehicle), in order to maintain the balance of the internal gas environment, it will exhaust gas into the waters through which it is sailing. In addition, due to the movement of the underwater vehicle and the rotation of the propeller, mixing in the surrounding waters will be caused. The physical or chemical features of the area are different from those in still waters, resulting in the so-called wake features. In response to these differences in characteristics, the development of physical or chemical feature detection methods and devices can indirectly detect, track underwater vehicles in the water. In the past few decades, research on the wake features of underwater vehicles has attracted more and more attention. The main research direction includes the thermal wake (Zhang, Yang, Yuan, Liu and Zhang, 2008), the internal wake (Zhao, You and Chen, 2009), the bubble wake (Gu, Tian, Zhang, AND Wang, 2012) and the bioluminescence wake (Cao, Wang and Luo, 2011).
The sources of the bubble wake of underwater vehicles mainly include gas emissions and motion cavitation. The main purpose of gas emission is to maintain the balance of the internal gas environment. Motion cavitation is caused by the relative motion of the underwater vehicle and the surrounding water under the condition of high-speed navigation. In order to suppress the bubble wake features of underwater vehicles, corresponding measures can be taken from the source. It is possible to transform gas into liquid or solid waste for control the bubble wakes produced by gas discharge. And the bubble wakes produced by motion cavitation can be weakened by the method of shape optimization. In addition, for the bubble wake in the near-wake region, the high frequency ultrasonic wave can be used to reduce the intensity of the bubble wake (Chen, 2004).
