Numerical study on the influence of nozzle divergence half angle on thrust oscillation characteristic of underwater jet power

Abstract Underwater rocket propulsion is increasingly used in advanced marine vehicles that may be subject to supersonic gaseous jets while submerged. This work investigates the influence of nozzle divergence on multi-flow field evolution process and thrust oscillation characteristics by multiple numerical simulations using a VOF multiphase flow model. Four half angles are taken into consideration. The analysis indicates rises sharply at closure opens, then rapidly decreases follows another rise. oscillates high frequencies. As result, increase angle leads size decrease bubbles but does not affect changing trends thrust. Increase reduction frequency oscillations.