A numerical investigation is made on the effects of location and shape of front wall of OWC (Oscillating Water Column) chamber on the hydroelastic response of VLFS. Most of studies on the effects of OWC chamber on response of VLFS have assumed the location of the OWC chamber at the front of VLFS. In the present study, an OWC-chamber is introduced at arbitrary position of VLFS to see the influence of the location and shape of OWC chamber on the hydroelastic response of VLFS. A finite element method is adopted as numerical scheme for fluid domain. Finite element method combined with mode superposition method is applied in order to consider change of mass and stiffness of OWC chamber in piecewise constant manner for analysis of the hydroelastic response of VLFS efficiently as well as modeling different shape and material property along the structure easily. Reduction of hydroelastic response of VLFS is investigated for various locations and front wall shapes of OWC chamber.
Attractive concept of using VLFS(Very Large Floating Structure) for utilization of ocean space has been widely adopted over the world and intensive efforts to develop design and analysis tools have been made during the last decade. One of main design concerns of VLFS is to ensure structural integrity as well as operability under harsh wave environmental conditions. Since the structural stiffness of such a huge structure is so weak that the deformation of the structure should be considered both for hydrodynamic wave loads and induced structural motions. This is the reason why various kinds of hydroelastic analysis methods have been developed to obtain more efficient and realistic solutions (Kashiwagi, 1999, Watanabe, 2004). Well known attractions when VLFS is adopted for ocean space utilization is the minimization of environmental impacts arisen when the conventional reclamation method is adopted,