Study On Underwater Noise Characteristics Of Ships In Complex Ocean Environment

Acoustic radiation and acoustic propagation characteristics in complex Marine environment are important indexes to measure the stealth safety of ships,which are the key contents for evaluating the acoustic performance of ships.For ships and offshore large complex structures,such as underwater vehicle in the far field noise should be analysis,construction of underwater noise detection efficiency of the numerical analysis method will be the effective guarantee of the vitality and improve ships is of great significance for the situational analysis,tactical decisions,research has important theoretical value and engineering application background.Taking the numerical analysis of underwater noise detection efficiency of ships as the research target and following the research method combining theory with engineering application,this paper studies the method of line spectrum noise detection efficiency of ships and explores the acoustic detection characteristics of complex Marine acoustic field environment.In order to analyze the detection performance of sonar receiving equipment,the acoustic detection model of underwater targets in complex Marine environment was constructed based on the passive sonar equation.Through numerical simulation of underwater target radiation sound source level,simulation of ocean sound field propagation loss and estimation of background noise level,the array response of receiving equipment is obtained through signal processing,and the target detection probability is determined based on statistical detection theory.Firstly,the acoustic-solid coupling theory and boundary element method,combined with the flow field truncation technology in infinite domain,are used to build the prediction model of the underwater radiated noise of ships,and the analysis of underwater acoustic radiation characteristics of ships is completed.Secondly,the theoretical methods of modeling ocean sound field are summarized.In view of the ray theory,the simple positive wave model and the parabolic equation model,the inherent limitations of modeling technology in the application of geometric relations,frequency calculation and other aspects are discussed,and the calculation results are verified to establish the calculation method of underwater acoustic propagation loss.Finally,based on the passive sonar equation,the performance modeling of linear spectrum acoustic signals is carried out,and the corresponding relationship between detection distance and detection probability of underwater noise of ships is analyzed.The detection efficiency of ship line-spectrum noise in deep water and shallow water is studied and the distribution law of sonar detection probability is discussed.It is considered that the detection probability of specified receiving equipment is a continuous function about the target position,the probability function gradient is solved,and the recursive algorithm of ship’s low noise trajectory is derived.On this basis,the factors affecting the detection performance of sonar are summarized to explore the distribution law of detection probability of sonar receiving equipment in complex Marine environment.Through the numerical analysis and theoretical derivation of acoustic radiation,acoustic propagation and sonar receiving equipment performance in complex Marine acoustic field environment,the detection efficiency analysis model for line-spectrum noise is established,and the low-noise route algorithm for underwater targets is proposed,which provides a new technical reference for the acoustic situation analysis of ships and underwater vehicles.The influence of boundary interaction,propagation path and volume effect of ocean acoustic field on the acoustic detection performance of underwater targets is given,which provides a new idea for the optimal design of the acoustic performance of ships or underwater vehicles.