Simulation And Induced Magnetic Field Distribution Characteristics Of Ship Wakes

The induced magnetic field(IMF),one of the important physical characteristics of wakes,plays an important role in marine exploration,targets tracking and anti-reconnaissance et al.The wake wave and velocity models are established based on Maxwell equations,theory of magnetic fluid dynamics,ocean wave spectrum and the geometric characteristics of ship theory,and IMF is modeled considering the actual marine environment and ship geometry as well as in this present paper.Simultaneously,IMF is simulated and analyzed based on Kelvin wakes in the process of ship driving by use of Matlab.The variation and distribution characteristics of IMF of ship wakes are reached,A feasible simulation software is configured for systematical chromatography of IMF of ship wakes.The main details of the paper are as follows.Firstly,Mathematical model of ship wakes waveforms is established.A wave model,based on theoretical calculation and analysis for different ocean waves,ship geometry,and navigation speed according to the characteristics of the wave spectrum theory is set up.Different geometric structures of underwater part of navigational body is simulated combing the model with computer software.1-3 dimensional space wake waveforms are analyzed and discussed in detail respectively,by integrating wake characteristics with main scales of ship hull.As such wake waveforms distribution and variation are reached.Secondly,Mathematical models of the wake velocity and the IMF of the ship is built.Mathematical model of velocity and IMF is set up based on the wake waveforms model by selecting P-M wave spectrum as that of sea surface in this present paper.The variation and distribution characteristics of wake velocity and IMF are analyzed under different sea conditions,different ship scales,sailing speed and wind speed at sea surface,and the relationship between the IMF and those parameters related is obtained.Meanwhile,the variation of the IMF with the propagation distance is achieved,and magnitude of IMF and its error of simulation results are analyzed in depth.The dynamic evolution of IMF of a single vessel with time and ship motion are simulated,and IMF of several ships is simulated based on superposition principle of magnetic field vectors,deducing from the analysis mentioned above.Thus the foundation for the design and development of IMF simulation system of ship wakes is certified with the investigation.Thirdly,a simulation system for IMF of ship wakes is designed.IMF simulation system is designed by use of GUI window programming in Matlab,combined with Matlab MCR and Microsoft Visual Studio 2010 compiler.This application program of simulation system,with several advantages of simulating the size and distribution characteristics of the IMF strength of ships in any direction accurately,intuitively and quickly,as well as convenient operation and cost saving,is free-running from Matlab environment.The system designed provides a better foundation and an effective simulation platform for ship wake simulation experiment and exploration of marine resources.Combing modeling and computer software,ship wake waveforms,velocity fields and IMF distribution are studied and analyzed in depth in the paper.Simulation results under various parameters and IMF are reached.The integration of the distribution model is achieved.Results in many aspects are of basic support for the detection and identification of Marine Targets.