Experimental Investigation of the effect of air injection rate behind the cone nose of an axi-symmetric body on the relevant super-cavity at different water flow velocities

In this paper, the characteristics of the ventilated cavitation around an axi-symmetric body with a cone nose at different water velocities and injection rates have been investigated experimentally. The experiments are done in an open loop water tunnel with a maximum water flow of 40 m/s. The main purpose of this research is to study the rate of air injection and the flow velocity on the coefficient of drag and the relevant super-cavity shape. The effect of air injection rates from end of the cone nose of the body on two phases fluid flow characteristics was studied for different water velocities within the tunnel. For each case of input conditions, the variations of the drag force and pressure distribution profiles along the length of the body and the length of the super-cavity are measured. The results of the present study show that increasing of the injection rate to an optimal value has a significant effect on the reduction of the drag force and after that the reduction of the drag force is negligible.