Numerical Investigation of Ventilated Cavities Around a Rudder-Equipped Axisymmetric Body

As an efficient drag reduction technique, ventilated cavity technology demonstrates significant application in underwater launch systems. This study employs numerical simulations to systematically examine the ventilated cavity flow characteristics and cavity–rudder interaction mechanisms for a rudder-equipped axisymmetric body. Numerical simulation predicts the gas leakage behavior, cavity geometry, and internal flow structure. The results indicate that the development of the ventilated cavity proceeds through three distinct stages: rapid growth, slow development, and quasi-periodic shedding. During this process, local high pressure at the leading edge of the rudder suppresses cavity growth, while cavity shedding is associated with re-entrant jet effects. Under the influence of the ventilated cavity, the overall load on the entire body and the local load on the rudder exhibit consistent patterns: Fx > Fy > Fz ≈ 0 and Tz > Tx ≈ Ty ≈ 0, with Fy and Tz fluctuating the most violently. The shedding cavity clusters are primarily concentrated at the rudder root during the quasi-periodic shedding stage.