Dynamic Analysis Of Underwater Towed Linear Array

Underwater towed system is widely applied in the domain of detection of marine resources,anti-submarine warfare,torpedo defense and index evaluation.Surface warship can greatly improve its underwater detectivity by towing a linear array.AUV(Autonomous Underwater Vehicles)with linear array can be torpedo acoustic decoy or target.The linear array is a key component of the towed system,and its underwater dynamic characteristics will influence the whole towed system's rapidity,maneuverability and sailing stability.So,the research about the underwater dynamic characteristics of towed linear array has very vital theoretical significance and practical engineering value.The purpose of the study presented here is to evaluate the underwater dynamic characteristics of towed linear array and influence on the sailing stability of towing carrier AUV,based on the project of navigable underwater acoustic target(NUAT).(a)In consideration of their force condition,a dynamic model of towed linear array and a six degrees of freedom(6-DOF)motion model of towing carrier AUV are established.Numerical methods of solving the model are determined,finite difference method is used to discretize the control equation,Newton iteration method and fourth order Runge-Kutta method are used to calculate the discrete equation.Based on MATLAB/ SIMULINK software,simulated program is developed.Through analysis of a typical example,the validity and reliability of this method are verified.It can be used to analyze the underwater dynamic characteristics and posture of towed linear array and towing carrier.(b)A design scheme about the towed linear array is presented according to the specifications of the NUAT project.The underwater dynamic characteristics and attitudes of towed linear array are obtained through a large of simulation runs.Different parameters can be varied,such as straight run,turning,different speeds,etc.Contrastive study about the motion of the AUV with and without linear array is done.The result of the study proves that the linear array has no obvious effect on the sailing stability of AUV and the design scheme is feasible.(c)To verify the accuracy of simulation result,an towing trial is designed and ran in the lake.This paper gives some results of lake trials and describes the underwater dynamic characteristics and attitudes of the towed linear array in both straight run and turning conditions.The simulation results are similar to the trial data,the validity and reliability of this simulation analysis method is verified.