Due to the different arrangement and control mode of an underwater vehicle with an X-rudder configuration, the effectiveness of the after-control-surface is influenced by the angle of incidence of the underwater vehicle.

Numerical simulation is carried out on SUBOFF model with an X-rudder configuration, including variations of single rudder coupled with attack angle and drift angle respectively, along with fitting research for each case.

The results show that the hydrodynamic characteristics related to rudder angle for the two orthogonal planes are different because of the significant interaction between the rudder and main body. The effectiveness of the top right rudder and lower left rudder decreases and increases with the incidence angle respectively for the studied range of incidence and rudder angle, and is also different from its straight running conditions. The relative change of the rudder derivative is up to 16% in quantity.

This study can provide references for the motion modeling and simulation evaluation of underwater vehicles with an X-rudder configuration.