Effects of scarfed jet configuration on the flow field and hydrodynamic characteristics of a supercavitating vehicle

Abstract

To enhance the tail-slap stability of the supercavitating vehicle during maneuvers, an active stabilization control method using aft scarfed gas jets is proposed. By establishing an unsteady gas–vapor–liquid multiphase coupled numerical model, the reconstruction mechanisms of the coupled flow field under varying nozzle scarfed angles θ and axial positions x0/L are analyzed. The results indicate that the scarfed jet enlarges the radial clearance between the vehicle tail and the cavity boundary, thereby providing a greater deflection margin for the longitudinal pitching. Regarding the total pitching moment coefficient and the center of pressure coefficient, as θ increases from 25° to 90°, both coefficients exhibit an initial decrease before flattening, which is attributed to the coupling of thrust vector attenuation and windward shoulder moment compensation. Furthermore, as x0/L shifts from 0.65 to 0.8, both coefficients increase monotonically, driven jointly by control moment arm extension and windward high-pressure region expansion. The jet-induced asymmetric surface pressure redistribution dominates the pitching moment variation, exerting a significantly stronger influence than the direct jet thrust. Overall, within the investigated parameter range, adopting a small scarfed angle and an appropriate rearward layout significantly enhances the longitudinal static stability characteristics of the vehicle under the operating conditions considered. Specifically, with θ  = 25° and x0/L = 0.8, the pitching moment coefficient increases by 152.5% relative to the baseline, while the center of pressure coefficient shifts rearward by 15.8%.