Investigation Of Cavity And Hydrodynamic Characteristic Of Vehicle

During the recovery process of the aircraft’s return capsule,projectiles and other underwater weapon,the huge impact probably results structures’ damages,changes of entry trajectory,or sensors’ and other inner components’ failure,etc.A series of complex physical changes occur when the vehicle falling into the water,and the surrounding flow field has a extremely influence on the motion process,which is a strong unsteady characteristic process.Therefore,a study on cavity and hydrodynamic characteristic of water recovery vehicle is of great significance to optimize the structures and operating conditions of the underwater weapon.A generic numerical simulation method is developed to investigate the characteristics of water cavity flow field.The method based on the N-S equation,taking the appropriate multiphase flow model and turbulence model.Fluent was taken as the computing platform,combined with dynamic mesh technology and user-defined functions.The validation of numerical model is examined through comparison with experimental results.The cavity and hydrodynamic characteristic during the vertical water entry are analyzed in this paper.The effects of water-entry velocity and angle during water entry which act on the formation and development of water-entry cavity,the hydrodynamic characteristic,as well as the flow field structure are investigated.In terms of hydrodynamic characteristics,the peak of the drag coefficient increases with the increase of water-entry velocity and angle.In terms of water entry cavity,the maximum diameter and the shrinkage rate of cavity increases with the increase of water-entry velocity,and decreases with the increase of water-entry angle.