Experimental investigation of water slamming loads on panels
Rigid-body slamming has become increasingly important as ships travel at higher speeds experiencing larger loads during hull impacts against surface water which can result in structural damage and crew injury. It is necessary to characterise the hydrodynamic loading during water impacts. We present a series of experiments conducted in order to study slamming force events seen by flat plates during free surface impacts. The experiments focus on the characterisation of the loads experienced by flat plates during the first phase of the slamming event, the water entry. They have been conducted in an especially designed test apparatus, the Slingshot Impact Testing System (SITS), which allows us launching objects against the free surface of an open channel, with the possibility of setting up different speeds and deadrise angles. We can study slamming with trapped air between the plate and the water free surface, at high impact speeds and small deadrise angles, allowing us to quantify the resulting cushioning effect. High velocity impacts up to 5 m/s were conducted at angles between 0.3° and 25°. It was found that the trapped air phenomenon significantly cushions flat plate impacts with angles less than 5° and impacts with larger angles adhere to Von Kármán's equations.
© 2011 Elsevier Ltd. Received 27 April 2010. Accepted 15 June 2011. Editor-in-Chief: A.I. Incecik. Available online 2 July 2011. Funding for the experiments was provided by the Office of Naval Research through Award Number N00014-06-1-0730. F.J.H.H. gratefully acknowledges the support provided by the European Commission through the Marie Curie IOF actions for individuals (PIOF-GA-2008-219429).