Abstract
Water impact accelerations of axially symmetric bodies are analyzed considering the flexibility of the bottom surfaces. The bottom surfaces considered are spherical shells. Four equations are derived to express this phenomenon. These are the equation of the motion of the bodies during water impact, the equation of the area of the bodies in the undisturbed water surface, the equations which give the pressure distribution on the bottom surfaces, and the vibrational equation of the spher- ical shells. These four equations are solved numerically and the results are shown in graphical forms.
The water pressure on the spherical shells is given by adding the pressure due to the velocity change and the expanding area of the body in the undisturbed water surface and the pressure due to the vibrational motion of the shells. The equation expressing the hydroelastic interaction between the vibrational motion and the water is derived by applying the method to write the velocity potential Φ on one side of an infinite plane (z=0) in terms of the value of Φ at points of this plane11).
The maximum accelerations calculated considering the interaction are much larger than the values obtained considering the bottom surface as rigid or neglecting the interaction. The analytical results including the hydroelastic interaction also show that the period observed in the acceleration curves is much longer than the free-vibrational period of the bottom surfaces.
