Spatial Evolution Analysis Of Wake Of Submarine Sailing Near Water

With the development of submarine noise reduction technology,it needs to develop new anti submarine technology to ensure the detection ability of submarine.Using SAR(synthetic aperture radar)and satellite can find Kelvin wave generated when submarine is sailing near the water surface.Therefore,the research on the characteristics of submarine wake is of great significance to the development of new anti submarine technology.In this paper,the international standard SUBOFF submarine model is used to study the development of surface wave and wake in different situations.First of all,the submarine movement in the basin is realized by using the overlapping grid,and the wave making model is added at the entrance to simulate the submarine navigation in the wave field,changing the wave height and wave length,and observing the change of the wave form of the free surface of the submarine.The results show that the Kelvin wave can still be seen above the submarine when the submarine is sailing in a limited wave area,but the propagation range is limited greatly,and the wave form of the wave is almost invisible.In the process of submarine movement,the pressure of the submarine body changes greatly because of the water standing and the hydraulic loss,which causes the pressure field of the surrounding waves to be greatly affected and the wave form to disappear.Secondly,taking into account the phenomenon of density stratification in the ocean,the density stratification is simplified to a strong stratification model for calculation.The velocity at the inlet of the basin,the density ratio of stratified fluid and the depth ratio of stratified fluid are changed respectively,and the influence of sea state change on internal waves is analyzed.The results show that the Kelvin wave on the free surface changes from S-wave to S-wave when the inlet velocity changes.The wave length increases with the increase of speed,and the internal wave becomes stable with the increase of speed.When the density of the lower layer increases,the disturbance of the submarine to the internal interface increases,and the influence of the internal wave shape is limited.When the distance between submarine and inner interface increases,the disturbance of inner interface decreases gradually,and the height of inner wave decreases gradually.Finally,change the attitude of submarine,calculate the free surface waveform of submarine at different angles of pitch.The results show that the wave height of the bow is higher than that of the stern when the center of the submarine is the same.The wave height of the free surface is independent of the length of the submarine in the direction of water flow.At the same speed,the maximum pressure in the bow is the same at different pitching angles,and the maximum pressure loss depends on the angle of attack of the submarine's command station.When the submarine is pitching,the deformation of the wake vortex behind the submarine is larger,and the closer it is to the free surface,the more obvious the deformation is.