Active Control Method For Low Frequency Noise Spectrum Of Underwater Structures

As an effective weapon in underwater combat,the acoustic stealth performance of underwater vehicles is very important.Reducing the radiation noise of underwater vehicles is one of the main measures to improve its acoustic stealth performance,mainly including passive noise reduction and active noise reduction.Passive noise elimination is more effective for noise control in the mid-high frequency,but it has certain limitations when applied in the low frequency range.In comparison,the active noise reduction method is easier to implement at low frequencies,and the theoretical noise reduction can reach a higher level.With the continuous development of digital signal processing technology and devices,the active noise control theory is gradually improved to make active noise control for underwater structure to be possible.Moreover,the low-frequency noise of large structures has the characteristics such as long wavelength,slow attenuation,and low directivity.Therefore,it is feasible to realize the whole space noise reduction.Aiming at the low-frequency noise line spectrum control problem of underwater structure,the active control method is researched in the paper.An underwater structure acoustic field active control method which is based on adaptive algorithm is proposed.The simulation calculation is carried out by numerical method,and the active control effects of different secondary sound sources and the investigated points positions have been discussed.An active noise controller based on adaptive algorithm has been built,and the low frequency noise line spectrum control experiment was carried out in the anechoic tank using underwater transducer and cylindrical shell.The simulation and experiment results show that the proposed active control method to low-frequency noise line spectrum of underwater structures has certain feasibility,and it has great advantages in low-frequency noise reduction of underwater structures.