Experimental investigation of ventilated supercavity of underwater bodies

In order to explore drag reduction of supercavity and guaranteeing forming supercavity in lower velocity, experiments of underwater bodies forming ventilated supercavity were performed in cavitation tunnel. Supercavity was formed using ventilation method in lower velocity. Changing ventilation volume and Froude number, a series supercavity lengths were obtained in different conditions and experiential formula of ventilated cavity length was presented. Experimental investigation shows that supercavity length increases with ventilation volume increasing at constant velocity, and ventilation volume reduces with Froude number increasing for some a supercavity length. Gravity causes ventilated supercavity serious asymmetry. Comparing vapor supercavity length with ventilated in the same cavitation number, Froude number effecting on ventilated supercavity length was quantified. Gravity effecting on ventilated supercavity length can be ignored at Fr = 43.74.