Water Wave Interaction By A Floating Cylinder In Presence Of A Coaxial Bottom Mounted Cylindrical Obstacle In A Two Layer Fluid

Abstract

This thesis studies the water wave interaction with two cylindrical structures in a two newlinelayer fluid of finite depth among which one cylinder is floating in the upper layer and newline the other is bottom-mounted which can be taken as a model of wave-energy device like newline point absorber. The main objective is to determine the hydrodynamic forces due to the newline diffraction and radiations by the cylinders. We solve this fluid-structures interaction newline problem based on the assumptions of time-harmonic and linear motion. newline The problem is mainly concerned with non-viscous incompressible fluid under the newline irrotational motion, neglecting the surface tension effect on the free surface of the fluid. newline This particular fluid-structure problem the fluid layers are considered to have infinite newline extent horizontally and of finite depth. The upper layer is bounded by a free surface newline while the lower fluid layer is bounded by a rigid impermeable base. Both the fluid lay newlineers meet each other at the interface between them. The first problem is considered for newline diffraction problem by both the cylinders. The other problems deal with the radiation newline problem assuming the upper cylinder undergoes oscillations causing radiation wave. newline Due to diffraction or radiation of linear waves, the potentials allows us to calculate newline the hydrodynamic forces acting on the cylindrical body and we observed the physical newline behaviour of the hydrodynamics forces due to both the diffraction and radiation case. newline Further studies of radiation problem split into various parts for a different mode of oscil newlinelation and translation motion. Both the problems i.e. diffraction and radiation case, are newline governed by three-dimensional Laplace s equation within each layer of the fluid region. newline The governing equation is combined with the free surface condition, hard bottom con newlinedition, interface conditions within the specified regions. To ensure the unique solution newline for both problems, we introduced infinity or radiation condition as the fluid domain newline extends to infinity in the horizontal direction.