Evolution of submarine wake and interaction with the free surface

The research on the evolution of submarine wake and its characteristics on the free surface is the foundation for analyzing the influence of the wake on sound transmission and for detecting submarines by remote sensing.Based on the model measurements and analysis,the formulae for predicting the evolution of submarine turbulent wake have been developed and expressed as function of submarine velocity,initial wake size,Brunt-Vaisala period,and time after submarine passage,and the wake characteristics on the free surface is summarized.The wake collapses due to the stratification results in a very flat and wide wake.When a submarine moves underneath free surface,the decay rate of flow velocity in wake is reduced because of the confinement of free surface.The interaction of turbulent wake with the free surface causes surface deformations and waves.These waves are generated by the large-scale vortical structure in the wake,which deforms the surface initially and "Breaks" it to form random waves eventually.