Experimental Validation of Pharwen Code Using Data from VAWT Wind Tunnel Tests with Imposed Motions

NENUPHAR, in collaboration with IRT Jules Verne and ECN (Ecole Centrale de Nantes) has performed extensive testing in a large wind tunnel (CSTB, Nantes) of a scaled-model of a two-bladed VAWT in the frame of the “MOQUA” project. The model was mounted on a 6DOF robot (hexapod) capable of imposing simple and combined motions to the structure. The wind turbine was operated at a TSR (tip speed ratio) of about 4 with simulated floater motions (surge, sway, heave, roll, pitch, yaw, and combinations of those). Measurements were carried out using several internal balances placed at the junctions of the rotor elements. Main tests objectives consisted in the validation of the unsteady aerodynamic behavior of the VAWT and in the validation of the PHARWEN numerical code, NENUPHAR’s simulation tool. The experimental validation strategy and results from the comparison between the experiments and the results of numerical simulations are presented in the paper, with a focus on the loads variation over one full rotor revolution that are specific to VAWTs.