Numerical Simulation for Ascending Trajectory of Submarine-Launched Carrier with Coupled Motion

The unpowered ascending trajectory of a submarine-launched carrier presents large angle of attack and side-slip angle due to the effects of launching condition and ocean current, and then shows nonlinear characteristics. The conventional trajectory prediction method cannot meet the requirement of practical application. In this paper, a three-dimensional computational model with six degrees of freedom is established based on dynamic mesh and spatial kinetic equation of rigid body to achieve a two-way coupled simulation of the carrier and external flow field. The unpowered ascending trajectory of the submarine-launched carrier is simulated by changing the initial conditions, and the results are compared with that of the MK46 torpedo trajectory model. The comparison shows that: 1) the pitching angle gradually increases during the ascending process, while the angle of attack increases first and then decreases; 2) the ascent pitching angle and peak angle of attack decrease with the increasing launching speed; and 3) the duration of ascent and the pitching angle of breaking out of water increase with the increase in launching depth. This study may provide a reference for prediction of enhanced maneuvering trajectory of undersea vehicles.