A comparison between the experimental and theoretical impact pressures acting on a horizontal quasi-rigid cylinder during vertical water entry

Abstract

This paper presents a detailed study on the local pressures acting on the surface of a quasi-rigid cylinder during vertical water entry into a flat water surface. This water entry event is an approximation of bottom wave slamming of cylindrical structures, which is a typical problem for many naval constructions. Hence, the results from this research can be used during the design of cylindrical structures in a slamming sensitive environment. The paper shows the impact pressure results of a large set of slamming drop experiments with a cylindrical model, on a rigorously instrumented test set-up using state-of-the-art equipment. The obtained experimental data is compared in detail with the governing theoretical formulations concerning cylinder slamming. For deadrise angles larger than 4.25°, a good agreement is found with an averaged version of the Wagner theory. This indicates that the Wagner theory is a good estimate for impact pressures acting on a horizontal rigid cylinder during vertical water entry, for deadrise angles larger than 4.25°.