The Hydrodynamic Noise Suppression of a Scaled Submarine Model by Trailing-Edge Serrations

Hydrodynamic noise seriously reduces the survival of underwater vehicles. The optimization of line type has been used to reduce hydrodynamic noise for a long history. However, the investigation on reducing hydrodynamic noise by flow control needs intensive study and further development. In order to reduce the hydrodynamic noise of the SUBOFF model, the hush characteristic of owls feather was applied to design the trailing-edge serrations of the sail hull. Numerical simulation is performed to investigate the effects of different serrations amplitude and serrations wavelength on the underwater noise from the model of SUBOFF. The results show that the hydrodynamic noise caused by the separation of the boundary layer and the shedding of the wake vortex has been reduced. The serrations with an amplitude of 0.1c and a chord length of 0.1h reduces hydrodynamic noise by more than 10dB in the frequency from 10 to 2000 Hz. The results provide method for the reduction of underwater noise by flow control.