Hydrodynamic response of a supercavitating vehicle to aft lateral-jet injection: Implications for attitude control

The tail-slap phenomenon encountered during the high-speed motion of supercavitating vehicles presents a significant challenge to conventional water-rudder control because it may increase hydrodynamic drag and cause thrust loss. To provide an alternative means of attitude control, this study investigates the hydrodynamic response of a supercavitating vehicle to an aft lateral jet and evaluates its attitude-control potential. A three-dimensional numerical framework combining the Volume of Fluid multiphase-flow model, the RNG k–ε turbulence model, and the Schnerr–Sauer cavitation model is employed to examine the interactions among the lateral jet, supercavity morphology, wetted regions, surface-pressure distribution, and vehicle hydrodynamic loads. The effects of freestream velocity are investigated over V = 60 -110 m/s. The combined effects of angle of attack and lateral-jet intensity are examined at V = 100 m/s, with α = 0°-5° and J = 0 , 0.003, 0.007, 0.013, and 0.029. The results show that the aft lateral jet does not fundamentally alter the overall topology of the supercavity but redistributes the local cavity geometry, wetted regions, and surface pressure, thereby producing pronounced changes in lift and pitching moment. At α = 5°and J = 0.029 , the drag and lift coefficients increase by 7.7% and 73%, respectively, relative to the no-jet condition, while the pitching-moment coefficient changes from a positive nose-up value to a negative nose-down value. Therefore, the lateral jet causes a certain increase in drag but substantially enhances lift generation and produces a pronounced nose-down static pitching-moment contribution at a large angle of attack. These findings demonstrate the hydrodynamic attitude-control potential of the aft lateral jet and provide a basis for further investigations of supercavitating-vehicle attitude dynamics and control.