Dynamic analysis of natural supercavitating flow during acceleration and deceleration of an axis-symmetric projectile

Supercavitation is an effective drag reduction technology for high-speed underwater vehicles. However, the evolution of supercavitating flow becomes more complex during acceleration and deceleration compared to steady-state conditions. This paper examines the unsteady supercavitating flow around an axis-symmetric projectile with disk cavitation subjected to various speed transitions. By utilizing the volume of fluid method, the large eddy simulation turbulence model, and the Kunz cavitation model, the study simulates and validates the dynamic behavior of the multiphase flow against experimental and published data. The cavity evolution during acceleration and deceleration is observed in three distinct stages. In the case of acceleration, the stages include initial stabilization, merging of the leading edge and shoulder cavities, and full supercavitation. For deceleration, the stages involve cavity collapse, trailing-edge cavity separation, and shoulder cavity formation. The study also highlights the presence of cavitation hysteresis, especially at higher acceleration and deceleration rates, which influences flow stability and drag reduction. This research provides insights for optimizing the design and control of high-speed underwater vehicles, where stable cavity formation is crucial for minimizing drag. Understanding how acceleration and deceleration influence cavity evolution can guide the refinement of cavitation designs and control strategies, improving vehicle performance during dynamic maneuvers.