Dynamic Analysis of a Floating Offshore Wind Turbine Under Extreme Environmental Conditions

Abstract

This paper is concerned with the development of a Floating Offshore Wind Turbine (FOWT) utilizing spar-type floating foundation. In order to design such a structure, it is essential to evaluate the dynamic response under extreme environmental conditions. In this study, therefore, a dynamic analysis tool has been developed. The dynamic analysis tool consists of a multi-body dynamics solver (MSC.Adams), aerodynamic force evaluation library (NREL/AeroDyn), hydrodynamic force evaluation library (In-house program named SparDyn), and mooring force evaluation library (In-house program named Moorsys). In this paper, some details of the developed dynamic analysis tool are given. In order to validate the program, comparison with the experimental results, where the wind, current and wave are applied simultaneously, has been made. The comparison shows that satisfactory agreements between the simulation and the experimental results are obtained. However, when VIM (Vortex Induced Motion) occurs, the current loads and cross flow responses (sway and roll) are underestimated by the simulation since the simulation code does not account for the effect of VIM.

Experimental Validation of Aero-Hydro-Servo-Elastic Models of a Scaled Floating Offshore Wind Turbine

“…A 1/10 scaled model of the stepped cylindrical shaped platform was deployed at sea in 2010 [10]. The feasibility of the hybrid-spar concept was confirmed through the study which lead to a half-scale prototype in 2011 [11] and full-scale prototype in 2013 which was also installed and tested at sea. The numerical simulations during power production showed good agreement and both prototypes even survived several severe typhoons [12].…”

“…is a matrix coupling the roll and yaw motion. The rotor aerodynamics will also couple with the drivetrain as the rotors aerodynamic torque will affect the drive train torque balance as seen in Equation (11). The drive train will affect the rotor aerodynamics by the rotational acceleration, speed and position of the rotor.…”

Floating Offshore Wind Turbine, Nagasaki, Japan

“…The wind-generated current speed is assumed to be linear up to 50 m from the sea surface. Figure 8 shows the schematic representation of the aero-hydro-servo-mooring dynamics integrated dynamic analysis tool used for the structural design (Utsunomiya et al 2012). The equations of motion for a whole system are generated and solved by a commercially-available multibody-dynamics solver (MBS), MSC.…”

Review of Experimental-Numerical Methodologies and Challenges for Floating Offshore Wind Turbines

“…And the validation for half size was in parked condition at NMRI (Kokubun et al 2012). Experimental descriptions aiming at a full scale have been given by their paper (Utsunomiya et al 2014), which introduced one dynamic analysis tool including MSC Adams (Jonkman and Buhl Jr 2005), NREL/AeroDyn (Laino and Hansen 2002), SparDyn (in-house) and Moorsys (in-house). His tests cover dynamic analysis and simulation validation of simplified scale model tests under extreme condition.…”