Active Noise Control Of Underwater Structure Using Parametric Secondary Sources

The active control of vibration and noise of underwater vehicle is of great significance to marine homeland security and economic construction in our country.With the continuous improvement of the low-frequency line spectrum noise detection performance in sonar systems,the technology of underwater vehicle noise control is facing more challenges.The lowfrequency noise control technology adopts the active noise reduction method to cancel the radiated noise of the controlled sound source on the sound propagation path.However,when the monitoring information is missing,the traditional active noise reduction method is inaccurate due to the inaccurate prediction of the sound field by the error sensor.The control effect is poor,and it may even lead to increased noise.In view of the above problems,this paper applies the multi-channel parametric emission method to the active control technology of underwater structure noise to solve the problem that the reliability of the traditional active noise reduction method decreases when the monitoring information is missing.First,using the sound pressure and vibration velocity information on the surface of the underwater structure,a far-field radiation noise prediction method based on the Helmholtz integral principle is established,and compared with the finite element method to verify the accuracy of the far-field noise prediction and determine the monitoring The principle of sensor placement provides the basis for input information for secondary sound source control.Secondly,a multi-channel parametric sound source sound field model is established to verify the controllability of the parametric secondary sound source sound field.The regularized least squares method control algorithm is used to realize the active control of underwater structure noise.the effectiveness of the algorithm.Finally,when the monitoring information is missing,combined with the far-field noise prediction of the underwater structure and the multi-channel parametric sound source feedback emission method,the local control strategy is adopted to simulate the effect of active control of the underwater structure noise when the monitoring information is missing.The results show that the accuracy of far-field noise prediction of underwater structures is the decisive factor affecting the effect of active noise control;the selection of parameters such as the direction of the secondary sound source collimating beam,the number of secondary sound sources and the number of far-field virtual reference points are also important factors.An important factor that affects the effect of active noise control.The collimation direction of the secondary sound source is distributed as evenly as possible within the full solid angle of the underwater structure.The greater the number of secondary sound sources and far-field virtual reference points,the better the noise control.favorable.In the absence of monitoring information,the local control strategy can improve the problem of the deterioration of the active control effect of underwater structure noise.The local control of the sound source is significantly improved in the low frequency range.In this paper,the multi-channel parametric emission method is applied to the active noise reduction technology of underwater structures.Taking advantage of the low frequency,broadband and high directivity of the parametric secondary sound source,a local control strategy is used to reduce noise in the accurate prediction area.Solve the problem that the lack of monitoring information makes the traditional active noise reduction effect worse,and improve the system reliability.At the same time,it can reduce the acoustic coupling between multiple channels,improve the stability of the multi-channel noise reduction system,and control the active noise of underwater structures.Technical application lays a theoretical foundation.