This benchmark focuses on the hydrodynamic interaction generated between two free moving flaps of a WEC system inspired by the Langlee device. This system has been used in the Wave Energy Converter Code Comparison Project (WEC3) [Combourieu2015]. The objective of this project was to verify and validate mid-fidelity numerical tools designed for WEC modelling in terms of multi-body dynamics and hydrodynamic interactions.
The floating device, inspired by the Langlee device, is composed of a semi-submersible base component with two aligned flaps as respresented in Fig. 48. The flaps are rigidely linked with a revolute link to the base component and free to oscillate around the y-axis. A power take-off (PTO) system, equivalent to the linear damping, is applied to the revolute link.
Main specification of the device are sumarized in the next table with PTO coefficients.
|Position||(0., 0., -8.5)||(-12.5, 0., -8.5)||(12.5, 0., -8.5)|
|Center of gravity (COG)||(0, 0, 0)||(0., 0., 3.5)||(0., 0., 3.5)|
|Pitch inertia (at COG)||7.65e7||1.3e6||1.3e6|
|PTO Damping (N.m.s)||4e7||4e7|
The base component is fixed in the world reference frame. Flaps are free to move relative to the base about their revolute joint. No PTO and viscous damping are applied in this test to compare with other numrerical models. The flap 1 initial position is set to 10°. Responses of the flap 1 and flap 2 are compared to other numerical results presented in [Combourieu2015].