Vortex Shedding Dynamics Behind a Single Solar PV Panel Over a Range of Tilt Angles in Uniform Flow

Solar photovoltaic (PV) panels are very slender structures that can be equipped with a tracking system to adjust their orientation and maximise their energy yield. Theses slender structures are exposed to wind loads and their aerodynamic response can vary considerably depending on the wind speed and operating tilt angle (theta) that can be in the range of +/- 60 degrees. Large-eddy simulations are performed to unveil the governing mechanisms involved in the vortex shedding and mean flow separation around a solar PV panel. Our results show that three regimes can be distinguished: at theta=+/- 10 degrees, leading-edge vortices are shed and convected along the panel's surface without significant flow separation; at theta=+/- 10 degrees-35 degrees, a low-frequency large-scale structure governs the vortex shedding with less-energetic tailing- and leading-edge vortices being shed at higher frequencies; and, at theta=+/- 35 degrees-60 degrees, the flow on the suction side is fully separated by non-symmetric vortex shedding due to the proximity of the structure to the bottom ground. The highest Strouhal number is observed for theta=+/- 35 degrees at which the tilt moment coefficient is also maximum. Decreasing the distance to the ground slightly increased the Strouhal number for negative tilt angles whilst no changes were observed for positive inclinations.