| In the actual ocean war,the wounded ships may be damaged by the second attack of underwater weapons.Therefore,studying on the shock wave propagation and bubble movement characteristics of the underwater explosion near the damaged structure is of great significance to the structural design of the warship and the naval combat strategy.This paper based on the Autodyn ALE fluid-solid coupling,the situation of underwater explosion near the intact solid structure and underwater explosion near solid structure with hole were studied.The weight of explosive,water depth,distance from the center of the explosive to the structure,vertical distance of the hole and the radius of the hole influence on the peak pressure,the velocity of the bubble boundary,the pressure of the water jet,the center movement of the bubble and the period of the bubble pulsation were analyzed.This paper first introduces the research background and significance of the research,presents the development of underwater explosion bubble motion theory,describes the mainstream military underwater explosion experiment and laboratory scale underwater explosion experiment method,and introduces the current process of commercial numerical simulation software and methods which can simulate non-spherical bubble movement well.The underwater explosion conditions of free field under different mesh densities,different model sizes,and different boundary conditions are simulated.Compared with the empirical formulas of shock wave pressure,maximum expansion radius of bubble pulsation,and bubble pulsation period,the existing experimental data are used to verify the reliability of numerical simulation.Get the suitable mesh density with the highest computational efficiency which can guarantee the calculation accuracy,the empirical formula for the overpressure of the shock wave in contact underwater explosion situation is fitted.Based on the previous text,the calculation model of axial symmetry model of underwater explosion with nearly intact structure,model of near broken rigid structure,non-axisymmetric underwater explosion model near rigid wall with the hole are established,the pressure measuring point is set on the rigid wall,horizontal distance non-dimension parameterγ11)),analyze the vertical non-dimension parameterγ?and the radius non-dimension parameter’s influence on shock wave propagation,bubble pulsation and the water jet phenomenon of underwater explosion,then study the dynamic behavior of bubbles after water jet.The purpose of this paper is to achieve numerical simulation methods for near-structure and near-break underwater explosion under different working conditions.This method is used to analyze the near-field underwater explosion shock wave and coupling the effects of structures,at the same time,to explore the less research condition of wall-attached jets of bubbles in the near-field and contact underwater explosion,and the interaction between the wall jets and the hole jets are discussed.Finally,the research work and deficiencies of this paper are summarized,and suggestions for further research are given. |
