• Journal of the Society of Naval Architects of Korea
• /
• v.54 no.6
• /
• pp.485-491
• /
• 2017

An experimental study on the reduction of vertical motion of floating body using floating-submerged body interaction was performed in a two-dimensional wave channel. The system consisting of a floating and submerged body that only move vertically was modeled. This experiment was designed based on the results of theoretical analysis of two-body interaction. The results showed a tendency to significant reduction of heave RAO of floating body due to submerged body. Various connection line stiffness and dimension of the submerged body were applied to investigate the effect of two-body interaction on the vertical motion of the bodies, Heave RAOs of the floating-submerged body were compared with those of single body. From the comparison study, we obtained an optimum condition of connection line and dimension of submerged body for maximum heave reduction at the resonant period of single body.

• Journal of Ocean Engineering and Technology
• /
• v.15 no.2
• /
• pp.11-21
• /
• 2001

The focus of this paper is on the numerical investigation of obliquely incident wav interactions with a system composed of fully submerged and floating dual buoy/vertical-flexible-membrane breakwaters placed in parallel with spacing between two systems. The fully submerged two systems allow surface and bottom gaps to enable wave transmission over and under the system. The problem is formulated based on the two-dimensional multi-domain hydro-elastic linear wave-body interaction theory. The hydrodynamic interaction of oblique incident waves with the combination of the rigid and flexible bodies was solved by the distribution of the simple sources (modified Bessel function of the second kind) that satisfy the Helmholz governing equation in fluid domains. A boundary element program for three fluid domains based on a discrete membrane dynamic model and simple source distribution method is developed. Using this developed computer program, the performance of various dual systems varying buoy radiuses and drafts, membrane lengths, gaps, spacing, mooring-lines stiffness, mooring types, water depth, and wave characteristics is thoroughly examined. It is found that the fully submerged and floating dual buoy/membrane breakwaters can, if it is properly tuned to the coming waves, have good performances in reflecting the obliquely incident waves over a wide range of wave frequency and headings.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2001.05b
• /
• pp.1133-1138
• /
• 2001

The focus of this paper is on the numerical investigation of obliquely incident wane interactions with a system composed of full submerged and floating dual buoy/vertical-flexible-membrane breakwaters placed in parallel with spacing. The fully submerged systems allow surface and bottom clearances to enable wave transmission over and under the system. The problem is formulated based on the two-dimensional multi-domain hydro-elastic linear wave-body interaction theory. The hydrodynamic interaction of oblique incident waves with the combination of the rigid and flexible bodies was solved by the distribution of the simple sources (modified Bessel function of fille second kind) tat satisfy the Helmholz governing equation. Using this computer program, the performance of various dual systems varying buoy radiuses and drafts, membrane lengths, clearances. spacing, mooring-lines stiffness, mooring types, water depth, and wave characteristics is thoroughly examined. It is found that the fully submerged and floating dual buoy/membrane breakwaters call, if it is properly tuned to the coming waves, have good performances ill reflecting the obliquely incident waves over a tilde range of wave frequency and headings.

• Selected Papers of The Society of Naval Architects of Korea
• /
• v.2 no.1
• /
• pp.18-28
• /
• 1994

In the vibration analysis of submerged or floating bodies such as ships and offshore structures, the coupled system between fluid and structure should be considered using the compatibility conditions on the wetted surface. It is well known that the hydroelastic vibration analysis of structures in contact with fluid can be done by applying the finite element method(FEM) to structures and the boundary element method(BEM) to the fluid domain. However, such an approach is impractical due to the characteristics of the fully coupled added mass matrix of fluid on the entire wetted surface. To overcome this difficulty, an efficient approach based on a reanalysis scheme is proposed in this paper. The proposed method can be applied for cases of higher local modes and beam-like modes for which three-dimensional reduction factors are not known. The three dimensional reduction factors are not needled and thus the restrictions can be removed in the analyses of non-beam like modes or local vibration modes by considering fluid-structure interaction. The validity and calculation efficiency of the proposed method are proved through numerical examples.