Dynamic characteristics and structural response of a supercavitating underwater vehicle: an experimental and numerical study

Supercavitating underwater vehicles experience unique stress states and dynamic characteristics compared to conventional underwater vehicles. This study investigates the structural behavior of a supercavitating vehicle under time-varying forces, focusing on the interaction between the nose cavitator and water, and the effects of tail-slapping. A supercavitating flow shell structure model experiment was conducted using a nose-mounted cable towing system, demonstrating significant drag reduction with increasing speed and a corresponding increase in tail-slap vibration. Numerical calculations revealed that the cylindrical shell section experiences the highest stress during tail-slapping, potentially leading to structural failure. High acceleration values during tail-slapping indicate extreme overload conditions. Structural reinforcement of the cylindrical shell is recommended. FEM analysis suggests that all parts of the supercavitating vehicle must avoid an operational frequency of approximately 18 Hz, and the junction between the conical and cylindrical shells should also avoid frequencies between 15 and 16 Hz.