Recently, large floating structures such as oil storage facilities and floating airports have appeared for the purpose of utilizing sea space and exploiting ocean resources. Many researchers have been developing artificial protective structures such as submerged breakwaters to prevent or decrease the actions of incident wave towards a coast. Therefore, it is necessary to estimate wave motion at a place where such structures are installed, and it is also important to consider the cases of undulated seabeds or bathymetric regions.
Rim Un Ryong, a researcher at the Faculty of Shipbuilding and Ocean Engineering, has studied three-dimensional water wave motion over undulated seabeds. For wave motion in sea water of finite depth, a fluid domain is usually unbounded horizontally but bounded vertically by free water surfaces and seabeds.
To study local wave motion over undulated regions only, he suggested a novel Dirichlet-to-Neumann (DtN) boundary condition on an artificial cylindrical surface by which a fluid domain is divided into an interior region with finite volume and an exterior region. Then, he applied the DtN boundary condition and other boundary conditions on mean free water surfaces and undulated seabeds in order to determine the solution to wave motion in the interior region by using Boundary Integral Equation (BIE). Upon verification of a submerged square cylinder, he extended the present model to the case of an array of rounded-rectangular cylinders or circular paraboloidal shoals.
The proposed model can be applied to assess wave motion over an undulated seabed when an undulated region is local and its surrounding region is horizontal and unbounded.
More information about this is found in his paper “An exact DtN artificial boundary condition for motion analysis of water wave with undulated seabed” in “Wave Motion” (SCI).
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