Scaling laws for the water entry of a three-dimensional body

Abstract

The present experimental investigation is a new way of conducting tests on model scale and of interpreting the results for the water entry of a free-falling conical body shape entrapping an air cavity. A three-dimensional body free to fall from different heights against a flat water surface is studied. Accurate measurements of the acceleration and velocity in water are performed; for the first time, local measurements of the pressure field in the air cavity entrapped behind the falling body are executed. The use of a depressurized channel enabled the scaling of the local loads as a function of Froude and Euler numbers. In spite of their uniqueness, the present results refer to one specific body shape and one specific mass-ratio value. Other similar studies are needed for a full comprehension of the universality of the scaling law for this physical phenomenon. The availability of such an experimental analysis enables a proper validation of the numerical models that can be, then, used for more general studies.