Acoustic Scattering Characteristics Of Ships Floating On The Undulating Sea Surface

The detection and identification of ship targets are of great significance to ocean remote sensing,maritime rescue and the tracking of military targets.Now it has become a hot spot in the field of marine research.Therefore,research on the scattering characteristics of ships on the rough sea has obvious engineering significance.Based on the theory of sound scattering from targets near the interface,this paper constructed the far-field calculation model for scattered field of a ship with the method of planar element,and obtained the calculation formula of the target strength under monostatic and bistatic conditions.At the same time,the paper used the computational software of Det Norske Veritas to calculate the ship's motions under the wave load.And with the data of ship motions and the file of finite element mesh as inputs,the model that calculated the characteristics of acoustic scattering from this target was proposed based on the method of planar element.The results of these computations turn out that there are two main factors influencing the far-field scattering characteristics of the target: the scattering area.After that,the paper studied characteristics of target strength for the rotated cylindrical shell.Results show that the rotated motion has a more obvious effect on the scattering characteristics in the far field.This proves once again that the scattering area contributes significantly to the target strength.For a specific ship model,Sesam software was used to calculate its motions under the undulating wave conditions.Firstly,the paper described the detailed process of the ship's modeling based on Det Norske Veritas Sesam software.In order to use the data of this ship's six-degree-of-freedom motion correctly,the coordinate conversion formula had been proposed.Based on the previous results and acoustic scattering theory,the paper studied the scattering characteristics of the ship under different wave conditions and concluded that the period of sea waves has greater impact on the scattering characteristics of the target than wave height and direction.