Floating body impact : asymptotic and numerical solutions

• Main Author: Iafrati, Alessandro
• Published: University of East Anglia 2009
• Subjects: 532.5015118
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501123

This thesis is concerned with the estimate of hydrodynamic loads generated during the water entry of bodies, originally floating on a still liquid surface. The analysis assumes the fluid to be ideal and the flow potential. The liquid is treated as incompressible, but the effects of weak compressibility are carefully estimated. A theoretical estimate of the loads in the early stage after the sudden start of the vertical downward motion of the body is derived. The solution is achieved through the method of matched asymptotic expansions, by using the non-dimensional body displacement as a small parameter. A uniformly valid solution is obtained by formulating an inner problem under suitable set of stretched variables and by matching its asymptotic behaviour with the inner limit of the outer solution. The boundary value problem governing the inner solution is strongly nonlinear, with nonlinear boundary conditions imposed on unknown free surface position. The solution is obtained through suitably developed numerical iterative procedures.