Numerical investigation of a canard configuration in flat turning of a vehicle at high-speed water entry

To enable the vehicle to transition quickly and stably to horizontal navigation during water entry, this paper proposes a horizontally symmetrical canard-wing configuration. The multiphase flow and kinematic characteristics of the vehicle with a canard wing during high-speed water entry were investigated using a numerical method. The research found that the water-entry cavity of the winged vehicle expands asymmetrically along the radial direction. The cavity expands along the wingspan direction, resulting in a non-annular profile at the cavity opening region. Additionally, the cavity closure time is later than that of the wingless vehicle. Detached, elongated vortex tubes are present on both sides of the wall near the tail region of the winged vehicle, and the vortex tubes are coupled with the tail vortex. However, the wingless vehicle exhibits only a ring-like vortex at the tail. Compared to the wingless vehicle, the canard configuration provides additional lift and moment components during the water entry. The hydrodynamic forces act continuously and stabilize the vehicle, making it achieve a horizontal attitude as quickly as possible. As the entry angle increases, the angular velocity and deflection angle of the winged vehicle decrease, while the flat-turning depth and flat-turning time increase.