Infrared Characteristics Analysis Of The Sea Surface Under The Coupling Effect Of The Submarine's Hydrodynamic Wake And Thermal Wake

With the development of military technology,the principles and technology of non-acoustic detection of submarines are getting more and more attention.And the infrared detection is one of the most important means of submarine detection within them.Thus,the infrared characteristics of the submarine wake on the sea surface have become a more and more important research direction.The submarine wake is mainly caused by the coupling of the hydrodynamic wake and the thermal wake.In this paper,the numerical analysis of the infrared characteristics of the sea surface under the interaction of the hydrodynamic wake and the thermal wake coupling of a submarine is analyzed.The model analysis mainly includes three steps:a)Establishing the self-propelled point analysis model,getting the the composite submarine's hydrodynamic performance and navigational states of equaling thrust and resistance in different speeds based on the self-propelled point;b)Studying on the mechanism of different navigation status effects on submarine hydrodynamic and thermal wake changes;c)Utilizing the spectrum of ocean waves to generate random sea surface and using the principle of linear superposition to obtain the wake characteristics of submarine random sea background,then studying on the infrared characteristic of the wake and generate the infrared image.The details are as follows:(1)The resistance value of submarine main body and the open water performance of propeller are analyzed based on ship hydrodynamics and the accuracy of the main body resistance prediction is verified by empirical formula based on flat plate hypothesis and then a thrust speed equation is given.Besides,the submarines' self-propulsion points with different speed coefficients are calculated and the influence of different navigation depth on the self-propulsion points are analyzed on the basis of take the additional resistance of the submarine and the reduction of the thrust of the submarine into consideration.(2)The submarine's hydrodynamic wake and thermal wake are analyzed under the coupling effect of flow and heat transfer when the submarine is sailing in uniform temperature and sea temperature.The generation,development and coupling mechanism of hydrodynamic wake and thermal wake under different parameters such as navigation depth,speed,cooling water discharge and propeller rotation are studied,and the wake characteristics of sea surface under the influence of various factors are compared and analyzed.(3)The data of the random wave height distribution of the given region are obtained by using the P-M wave spectrum on the basis of the wave spectrum summarized by the predecessors;then the wake of the submarine under the random sea surface background is obtained by using the linear superposition principle;finally,the infrared characteristics of the near,middle and the far wake region of the night submarine are analyzed based on the infrared calculation theory of sea surface and target,and the infrared imaging is carried out.