Influence of Wind Unsteadiness and Inhomogeneity on the Mean and Fluctuating Aerodynamic Force Acting on a Wingsail
Clément Bouhourd, Laurent Perret, Carlo CossuAbstract
The unsteady aerodynamic forces acting on a single wingsail immersed in turbulent atmospheric surface layer winds are numerically investigated by means of a blade element method with unsteady aerodynamic force modeling combined with a free-vortex wake model, which are standard tools in the wind energy community. We show that the root mean square (RMS) fluctuation amplitudes of the aerodynamic force range from 15% to 40% of the mean value when the true wind mean velocity is higher than the ship velocity. Peak fluctuation amplitudes are two to three times higher than the root-mean square amplitudes. We also show that the mean aerodynamic force is only slightly reduced when computed using the fully turbulent wind instead of the mean wind profile.
Keywords
unsteady aerodynamics; wingsail; WASP; atmospheric turbulent boundary layer; large eddy simulation; blade element method