Mathematical modeling of the oblique water-entry of cylindrical projectiles

Water-entry is the process in which a moving body with an initial velocity impacts the free surface and enters the water from the air and has many important applications in different fields of science and engineering. In this paper, a new transient model of the cavity shape by the consideration of the memory effect of the cavity is developed to predict the shape of the water-entry cavity for circular cylinders and this model has been used to develop the complete model of the oblique water-entry of a cylindrical projectile. The proposed model could predict the impacts of the cavity on the cylinder body and it is tried to take into account all of the forces and moments which act on the projectile in order to develop an accurate model for the water-entry problem. The simulation results of several oblique water entry of cylindrical projectiles in different angles show that the new proposed model could predict the projectile attitude and the trajectory of the projectile with good accuracy relative to the experimental data of water-entry and in a relatively shorter time of simulations compared to the numerical studies.