Adaptive Control Method For Underwater Low Frequency Noise Based On Phased Array

As an important underwater detection platform,the radiated noise of underwater vehicle not only exposes itself as the main feature,but also is an interference source to its own acoustic detection equipment which affects the detection distance and accuracy.Effective control for the radiated noise can improve its concealment and combat ability.At present,the active control method for underwater vehicle radiated noise has attracted wide attention,but it is difficult to achieve effective reduction of full-space sound field for large-scale complex structures.Therefore,how to use finite secondary sound sources to achieve noise control of main radiated azimuth has very important research significance and application value.The general idea of this thesis is to start with the array antenna theory and phased array technology,and to actively control the low frequency radiation noise based on the directional control of the secondary sound source array.Firstly,the array theory and array phase-controlled deflection are introduced,and the array orientation diagrams of different formations and angles are derived from the array theory,as well as the influence of array delay on the beam orientation angle.Secondly,the theoretical basis of active noise control based on sound wave superposition principle is introduced,the secondary sound source is changed from a combination sound source to an array form.The secondary sound source produces a sound wave with the same amplitude and opposite phase as the main sound source to reduce the noise at the error point.Thirdly,the sound field characteristics of the combined pulsating spherical sources are analyzed by numerical analysis,and the noise control effects of linear array and planar array in different directions are compared.Fourthly,taking an underwater cylindrical shell as the basic model,the numerical simulation analysis of the low-frequency radiation sound field control effects based on phased array is carried out.Finally,the active control experiment is carried out in the anechoic pool.Simulation and experimental results show that the proposed active control method based on phased array can achieve the directional control for the low frequency noise.