To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conduc...To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°.展开更多
The tuneable effects concept is aimed at achieving selectable blast and fragmentation output,to enable one charge to be used in different scenarios requiring different levels of blast and fragmentation lethality.It is...The tuneable effects concept is aimed at achieving selectable blast and fragmentation output,to enable one charge to be used in different scenarios requiring different levels of blast and fragmentation lethality.It is a concept Qineti Q has been developing for an energetic fill consisting of three principal components arranged in co-axial layers,two explosive layers separated by a mitigating but reactive layer.The concept was originally designed to operate in two modes,a low output mode which only detonates the central core of high explosive and a high output mode which detonated both the central core and outer layer of the explosive.Two charge case designs where manufactured and tested;one of these designs showed a reduction in blast and fragment velocities of^33%and^20%,respectively,in the low output mode.展开更多
基金supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX24_0714).
文摘To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°.
基金financial support of the Anglo-French Materials and Components for Missiles, Innovation and Technology Partnership (MCM ITP) program jointly funded by UK MoD (Dstl) and DGA
文摘The tuneable effects concept is aimed at achieving selectable blast and fragmentation output,to enable one charge to be used in different scenarios requiring different levels of blast and fragmentation lethality.It is a concept Qineti Q has been developing for an energetic fill consisting of three principal components arranged in co-axial layers,two explosive layers separated by a mitigating but reactive layer.The concept was originally designed to operate in two modes,a low output mode which only detonates the central core of high explosive and a high output mode which detonated both the central core and outer layer of the explosive.Two charge case designs where manufactured and tested;one of these designs showed a reduction in blast and fragment velocities of^33%and^20%,respectively,in the low output mode.
