Investigation On Prediction Method Of Deep-sea Sinking Position And Penetration Situation About Wrecked Space Vehicle

With the increasing number of deep-sea activities such as the launch of maritime rockets,the probability of accidents in the deep sea has also increased accordingly.After a deep-sea accident,it is necessary to make a rapid emergency response,quickly detect and salvage space accident equipment,and protect the core national technology.After the crash of aerospace equipment such as rockets,aircraft will experience three stages of high-speed slamming into the water,sinking under water without power,and penetrating into the mud,and eventually buried or semi-buried in the seabed sediment.The rapid detection and search of space crash equipment is the country Important guarantee for deep-sea activities;due to the complexity of the marine environment,the wreckage of the wrecked spacecraft is difficult to determine the landing point and sinking situation,resulting in high deep-sea operation costs.If it is possible to predict the distribution of the landing points of the spacecraft wreckage and the sinking situation,it will be possible to allocate search resources reasonably and effectively,reduce the cost of deep-sea operations,and increase the probability of successful deep-sea search.In response to the above problems,this article has carried out related research on key issues such as the deep-sea landing point of the wrecked aerospace equipment and the sinking situation.First of all,based on the actual deep-sea search needs as a research background,the domestic and foreign research status and current problems are introduced,and then the three key issues of spacecraft wreckage slamming into water,unpowered sinking under water,and penetration into mud are studied separately.Finally,the actual spacecraft was used as the research object,and its crash course was deduced and simulated.The research work of this paper is as follows:(1)Use VOF multiphase flow and natural cavitation conditions to establish a numerical model of target slamming into the water;predict the slamming load,resistance coefficient Cd,speed,acceleration and other physical quantities of the cylinder;numerical calculation results and test results A comparative analysis was performed to verify the reliability and rationality of the proposed method.Finally,hydrodynamic parameters such as the drag coefficient Cd were used as initial conditions and substituted into the six-degree-of-freedom motion equation of the sinking stage.Based on this,taking the cylinder as the research object,the effects of slamming speed,warhead shape,and cylinder density on physical quantities such as the drag coefficient Cd are discussed.(2)Establish a six-degree-of-freedom motion equation of the target under water for unpowered sinking based on MATLAB.Substitute the hydrodynamic parameters such as the resistance coefficient Cd obtained during the slamming phase into the water.At the same time,introduce the effects of random currents according to Monte Carlo ideas to construct The underwater motion model of the target based on Monte Carlo idea is used to predict the target's motion trajectory and the distribution of the falling points;the numerical calculation results are compared with the experimental results to verify the validity of the method in this paper.Posture is used as the initial condition for penetration into the mud stage.Based on this,taking the cylinder as the research object,the effects of the density of the target object and the drag coefficient on the dispersion of the falling points are discussed.(3)Use the ALE method and non-reflection boundary conditions to establish a numerical model for the target to penetrate the soil sediments;take the anchor as the research object,predict the depth of the mud,the impact energy,and the acceleration of the anchor,and compare the numerical calculation results with The test results were compared and analyzed to verify the effectiveness of the method.Based on this,the influence of the target mass,speed,penetration attitude,soil parameters and other factors on the depth of mud was discussed with the cylinder as the research object.(4)Use the key technology of water-in-mud entry proposed in this paper,the actual spacecraft wreckage was selected as the research object,and the overall history of the aerospace equipment crash was simulated,which further verified the feasibility of the water-in-mud prediction method.The research work in this paper can provide some theoretical guidance and technical support for the detection and search of actual deep-sea crash equipment,and can also provide a certain reference value for related deep-sea operations.