work the WEC is considered to have one degree offreedom (DOF), connected to the FOWT heave DOF
through a spring-damper coupling.
The motion in heave of semi-submersibles sized for multi-megawatt wind turbines is significant and
increases loading on various system components. Therefore it would be beneficial to reduce the platform
heave motions to allow for reduced structural loading and hence cheaper capital and operational costs. In
fact heave bottom plates have been employed on the WindFloat large-scale prototype installed off
Portugal to reduce the platform heave motions [7].
As mentioned before, this is an initial investigation into the effect of a hypothetical WEC on a floating
wind turbine. In this study no specific geometrical design of the WEC was set, and hence since the
hydrodynamic characteristics are largely dependent on the geometrical shape, they were not considered in
the analysis. Whilst the inclusion of the frequency-dependent added mass and damping terms would
affect the final results, the above methodology applied here would still be valid once a geometrical WEC
design is specified.