Research on the submarine floating movement in waves involving the water holes

When a submarine with a large volume superstructure floats up, the water on the back of the superstructure is large. In order to ensure the safety of submarine floating, it is necessary to study the stability and attitude change of submarine floating. In the present study, STAR-CCM + software is used to construct a numerical wave pool based on the numerical wave making theory. Based on the overset grid, the calculation method for internal and external domains interaction is adopted, and the uncertainty of the numerical calculations is analyzed using the model floating test results. What's more, the numerical results of the hull longitudinal and vertical velocities, and heel and pitch angles are close to the test results, except for the peak values. Compared to the test results, the average error of the amplitude of the numerical results was within 10%.It can thus be concluded that the numerical simulations were credible, which confirmed that the proposed numerical method can be applied to simulating the emergency ascent of a submarine with flow holes. Finally, a numerical prediction method for submarine floating movement in waves considering the superstructure water hole is proposed. The characteristics of the submarine buoyancy and emergence in waves are explored for various wave directions, wave heights and wavelengths. The results indicate that beam waves have a greater impact on the lateral orientation of the submarine, while the head waves are more effective on the longitudinal direction. Furthermore, the heel angle of the submarine is higher in beam and oblique waves compared to that in head waves. The longitudinal displacement shows a descending trend as the wave height increases. As the submarine exits the water, the hull posture is affected by waves, and the heel and pitch angles tend to increase by the rise of wave height. Based on a given wavelength range of 1∼3L, the higher wavelengths increases the longitudinal and lateral displacements of the hull, and reduces its heel and yaw angles. For shorter wavelengths, the hull responds faster to variations induced by the wave disturbances. It can be concluded that submarines should avoid surfacing in shorter wavelengths as well as in beam waves. The proposed numerical methods and conclusions of the present study can be considered as a reference in the scope of submarine floating movement.