Study on drag reduction and lift characteristics of ventilated supercavitating vehicle under the synergistic effect of multiple parameters

Underwater supercavitating vehicle is a kind of high-speed vehicle that uses artificial ventilation or natural cavitation effect to form a encapsulated air cavity (supercavity) on the surface of the vehicle to greatly reduce the water resistance. In this paper, through the water tunnel experiment, the cavitation is formed in the head of the vehicle. The six-component balance and the data acquisition system are used to obtain the hydrodynamic force of the vehicle. At the same time, the high-speed camera is used to obtain the cavity morphology and evolution process. The influence of cavitator diameter, ventilation volume, and incoming flow velocity on the drag reduction and lift characteristics of the vehicle is analyzed in depth, and the spectrum analysis is carried out. The experimental results show that when the transparent cavitation is formed, the drag reduction rate and lift force increase with the increase in the diameter of the cavitator, but when Dn/D = 0.3, the cavity necking is severe, resulting in a decrease in the drag reduction rate. With the increase in ventilation volume, the drag reduction effect is also getting better, and the drag reduction rate is up to 60.11%, but the lift shows a trend of increasing first and then decreasing. Increasing the inflow velocity, the drag reduction rate increases, and the lift shows a decreasing trend. The research results provide insights into the dynamic behavior of the flow field around the underwater supercavitating vehicle, drag reduction, and cavitator design.