EFFECT OF NOSE-CONE SHAPE ON IMPACT AND RICOCHETING OF A CANNONBALL COLLIDING WITH SEA SURFACE

摘要

When a cannonball collides with sea water, the resulting impact force influences the cannonball trajectory, depending on launching angle, initial firing speed, incident angle, and cannonball nose-cone shape. In this study, the effect of nose-cone shape of a cannonball on impact and ricocheting behavior was investigated. During collision, the flow is assumed to be non-viscous and incompressible, and a source panel method is used to determine velocity potential and pressure coefficient. The nose-cone shape was expressed by Haack-series. It is found that as the radius of curvature of a cannonball nose-cone decreases, a high impact force is resulted, and that the ricocheting distance varies depending on impact force and impulse. The results obtained in this study can be used in developing new cannonballs.