Study on self-noise suppression technique inside towed line array

Abstract Towed line array is an important equipment for long-range detection, but its self-noise seriously affects detection performance. In this paper, a jet release method based on fish slime is proposed to reduce the hydrodynamic noise of towed arrays. The purpose of this method is to reduce the adverse effect of the turbulent pulsating pressure generated by high-speed towed arrays on self-noise and to solve the problem of target signal masking caused by water current noise. An annular nozzle is installed at the front end of the towed array, and slime is sprayed backwards to reduce the turbulent pulsation pressure on the surface of the towed array and improve the signal-to-noise ratio. Large eddy simulations are performed using Fluent and finite element calculations of the acoustic field are conducted using Actran to obtain the flow and acoustic field results, respectively. The viscous drag of the model is reduced after spraying mucus through the nozzle, the surface excitation is remarkably reduced, and the self-noise sound pressure level is substantially reduced. On this basis, experimental tests are conducted in a gravity-type low-noise water hole, and the test results show that the proposed method is indeed effective in reducing the self-noise of towed arrays. The results of this paper lay a technical foundation for the self-noise suppression of towed arrays and have satisfactory reference value.