Simulation Research On Sea Surface Reflection And Targetion Characteristics Of Full Appendage Submarine

With the development of submarine vibration and noise reduction technology,it is more difficult to use the traditional way to detect submarine.Therefore,it is of great significance to explore a new submarine detection system for the maintenance of China’s marine security.The laser radar is a new detection system which is separated from the traditional way to identify the sea surface reflection of submarine dynamic wake.In this paper,through the flow field simulation of the dynamic wake of the full appendage submarine,combined with lidar imaging and pattern recognition technology,the sea surface reflection and target characteristics of the dynamic wake of the full appendage submarine are simulated.Firstly,the gas-liquid interface two-phase flow calculation method is used to simulate the wake flow field of submarines with different depths and speeds.The spatial evolution of wake flow characteristics of submarines under different motion parameters without sea waves and the distribution characteristics of sea surface reflection of submarine dynamic wake are analyzed.The results show that the different motion states of the submarine have obvious influence on the eddy current in the wake of the submarine,and the amplitude of the sea surface reflection wave of the dynamic wake decreases sharply in a certain wake length range,and remains basically stable in a longer range.Secondly,the wave making model is used to simulate the flow field of regular sea waves,and the flow field of submarine wake under regular sea waves is simulated.It is verified that the linear superposition of the sea swell wave height and the sea reflection wave height of submarine wake without sea waves is reasonable to simulate the sea reflection wave of submarine wake with sea waves.The results show that the linear superposition method is feasible and has high image similarity.Finally,by combining the improved Longuet-Higgins model with the fractal sea surface model,the random wave model is established,and the amplitude distribution characteristics of sea surface waves under different wind fields are analyzed.It is found that the wind field parameters have obvious effects on the wave distribution of different scales.In this paper,lidar intensity images are used to analyze the sea surface reflection of submarine wake under the condition of random waves.80 groups of submarine sea surface reflection intensity images with or without random waves are used as experimental data for feature principal component analysis(PCA)dimension reduction and error back propagation(BP)neural network training.It is proved that the recognition of submarine reflected waves is effective under certain sea conditions,but there is no absolute negative correlation between the recognition rate and the complexity of sea conditions because the frequency of submarine generated waves is different from that of random waves.