大口径锥头弹体高速倾斜入水偏转规律数值模拟OA北大核心CSTPCD

Integrated with a high-velocity oblique water entry test of a large caliber conical nose projectile,the deflection behavior of the projectile obliquely entering water was studied based on the arbitrary Lagrange-Euler (ALE) fluid-structure coupling method. Firstly,based on the experiment of a projectile impacting an inclined water tank at a high velocity,a finite element model was established to simulate the corresponding response characteristics,and the rationality of the numerical model and related method was verified. Secondly,the variation of the contact force mode and load characteristics of the projectile when the water entry velocity was 500 m/s was analyzed,and the corresponding mechanism was discussed. In addition,the influence of water entry angle on the deflection behavior of the projectile was investigated. The related analysis demonstrates that the projectile will deflect upward due to the effect of pitch moment,and the deflection velocity increases first and then decreases gradually during the entry process. The variation trends of deflection degrees are different within different entry angle ranges. When the entry angle is less than 15°,the projectile jumps usually out of the water. When the entry angle is in the range from 30°to 60°,the deflection trend of the projectile is almost the same,i.e.,the projectile rotates from the initial tilted state to a horizontal state,then to a vertical state,and moves finally downwards with its nose in the opposite direction to the initial water entry direction. When the entry angle increases to 75°,the projectile cannot continue to rotate to a vertical state after it rotates to a horizontal state,but instead moves downwards in a tilted state with its nose facing upwards. Under different water entry angles,the axial force exerted on the projectile is negative,leading to a continuous decrease in the projectile velocity. Comparatively,the transverse force is positive,and the peak value decreases with increasing water entry angle. Moreover,the penetration depth of the projectile increases with the increase of entry angle,and it almost shows an exponential relationship.