Research On The Motion And Load Characteristics Of Near-Field Underwater Explosion Bubbles Under Multi-Azimuth Curved Surface Boundary Conditions

The submarine may be attacked from any direction in the water.With the rapid development of guidance technology,the possibility of submarines being hit by underwater weapons at close range is also increasing.The curved surface boundary is the main structural form of the submarine.Under the influence of different azimuth curved surface boundaries,underwater explosion bubbles will show different motion characteristics,resulting in different bubble loads.In the near-field underwater explosion,the bubble loads is also one of the main factors causing submarine damage.In order to analyze the motion and load characteristics of the bubbles under the curved surface boundary of different azimuths,this paper uses the CEL method numerical simulation combined with the electric spark experiment to study it.The experimental results are used to prove the accuracy of numerical simulation,and numerical simulation is used to supplement the working conditions that are difficult to complete in the experiment.The methods are combined with each other to make the research of this article more perfect.Firstly,the CEL method is used to simulate the whole process of the pulsation of underwater explosion bubbles in the free field.Through comparison with reference experiments,the accuracy of the CEL method in simulating underwater explosion problems is verified,and the pre-processing settings such as material parameters,state equations,and boundary conditions are determined.Then,the underwater explosion problem near the free surface is simulated,and the cavitation truncation model is introduced to consider the cavitation effect near the free surface.Then analyze the ring-shaped bubble movement and the phenomenon of free surface water mounds,and further prove the accuracy of the CEL method through the electric spark experiment.Analysis and exploration of bubble motion characteristics under surface boundary conditions.By defining the polar coordinate system,the azimuth of the curved surface boundary is expressed by the two parameters of the dimensionless explosion distance y and the polar angle θ.Then,the two parameters were changed to set different working conditions,and the numerical simulation and experimental research under the boundary conditions of the multidirectional curved surface were completed.It mainly analyze the influence of γ and θ on the bubble’s motion shape,pulsation period,jet form and jet direction,and give the rule of the bubble jet shape and jet direction with the direction of the curved surface boundary.Due to the need to carry out a large number of numerical simulations of working conditions,the second development of Abaqus software is carried out in this paper,which greatly reduces the time required for pre-simulation processing.Finally,based on the load data measured by the pressure sensor in the experiment,combined with the previous analysis of the bubble motion characteristics,this article explores the bubble load characteristics under the boundary conditions of the curved surface.It mainly analyzes the influence of and on the type,peak value,pulse width,and generation time of the bubble load,and gives the change rule of the bubble load peak value with the direction of the surface boundary.The purpose is to find the best attacking position of underwater weapons,and to provide reference for the research of submarine anti-knock and anti-shock performance.