강체 연결체를 고려한 복수 Spar형 부유체의 거동 해석

Abstract

In this paper, wave-induced motion characteristics of multiple Spar-type floaters with rigid connectors and linear spring mooring lines are investigated. This is a fundamental study for developing the numerical simulation tool for an arbitrary floating wind farm. Hydrodynamic coefficients are achieved by using wave Green function method with High-Order Boundary Element Method(HOBEM). The effect of a rigid bar and mooring lines on the global stiffness matrix is adopted with the assumption that the motion response is comparatively small. Aerodynamics and rotor dynamics are not considered at this phase. One body simulation result has a good agreement with the previous experiments. Then, for two bodies simulation, some variables of a connector such as drag coefficient, installation point, weight are changed to identify the proper connecting mechanism. There is no significant change with variation of connectors characteristics except for connector mass, unrealistic connector link stiffness. Finally, the wind farm concept is considered with four floater which are arrayed as a square. Even though, the coupling effect of connectors and floaters is more complicated, the motion response is relatively similar as two floaters case. However, the sway motion is enlarged by drag forces on the connectors which is not observed in the two floaters simulation.