Numerical Study on Hydrodynamic Characteristics of a Supercavitating Vehicle During Booster Separation

The application of a staged booster system can significantly extend the operational range of a supercavitating vehicle. Booster separation from the main body within the supercavity, followed by its downstream movement and exit from the cavity, constitutes a key process in the realization of this technology. To investigate the hydrodynamic characteristics of the vehicle’s main body during in-cavity booster separation, an unsteady numerical study was conducted using the finite volume method, the Volume of Fluid (VOF) multiphase flow model, and a dynamic mesh technique. The evolution of cavity morphology and the corresponding hydrodynamic characteristics of the main body during the booster separation process were obtained. Furthermore, the effects of the relative separation velocity and separation distance on the hydrodynamic characteristics of the vehicle were analyzed, and the primary mechanisms responsible for the complex variations in hydrodynamic forces were clarified. When the booster separation velocity is not greater than the free-stream velocity, the hydrodynamic forces of the vehicle remain stable. When the separation velocity exceeds the free-stream velocity, the hydrodynamic forces undergo significant changes as the booster moves to a position approximately 0.75~1.0L downstream of the vehicle. A novel numerical approach based on the conventional dynamic mesh technique was employed to simulate two-body separation inside a supercavity, providing a new perspective for future investigations of multistage booster systems for range extension of supercavitating vehicles.