Experimental investigation of ventilated supercavitation behind cone-shaped with different angles and disk-shaped cavitators

Abstract

This paper systematically investigates the effect of the cavitator shape on the characteristics of a ventilated supercavity. These characteristics include ventilation demand, pressure behavior, and deformation of the supercavity due to gravity under different flow conditions. Four cavitators of different cone angles (45° cone, 90° cone, 135° cone, and 180° cone - disk cavitator) with the same diameter are applied in the experiments. The results reveal that a cavitator with a smaller cone angle requires less ventilation gas to generate and maintain a transparent supercavity than cavitators with a larger cone angle at the same Froude number. In addition, the formation gas ventilation coefficient tends to decrease with a maximum reduction of 27% corresponding to the 135° cone cavitator; however, the collapse gas ventilation coefficient remains almost unchanged as the Froude number increases. The pressure behavior inside the supercavity is investigated using two different monitoring positions. The pressure measurement close to the rear of the supercavity is slightly higher than that near the wake of the cavitator, and the pressure inside the supercavity becomes more uniform with an increase in the Froude number. Moreover, the effects of gravity on the ventilated supercavity geometry under different cavitator shapes and flow conditions are quantitatively investigated. The results show that the centerline of the supercavity becomes more straightforward with a further increasing Froude number, and changes in cavitator shape have a slight effect on the deformation of the supercavity.

Keywords

• supercavitation
• Cone angle
• Ventilation gas