An experimental study of aerodynamics on cable-supported photovoltaic panel arrays at different tilt angles

This paper presents an experimental investigation of unsteady aerodynamic lift and overturning moment on cable-supported photovoltaic (PV) panel arrays. Unlike prior studies focusing on area-averaged and peak pressure coefficients, this work examines second-order statistics of aerodynamic forces by analyzing fluctuating pressures on scaled models of PV panel rows. Wind tunnel tests were conducted on panels at different tilt angles, with synchronized pressure measurements used to compute aerodynamic coefficients, spectra, correlations, and coherences for lift and overturning moment. Results demonstrate that spanwise correlations and coherences of these aerodynamics exceed those of incident turbulence for most cases. The two-wavenumber aerodynamic admittance model, defined as the product of a 2D aerodynamic admittance function (AAF) and a spanwise correction factor, was employed to characterize unsteady wind loads. For zero tilt angle, the 2D AAFs for lift and moment deviated from the Sears function, displaying a transitional region where values surpassed the Sears function. For tilted PV panels, distinct peaks in the AAFs at elevated wavenumbers were observed, linked to shear layer instabilities in the leading-edge separation zone. An empirical model for the 2D AAF was proposed, which incorporates a correction term to capture these peaks, highlighting their significance in buffeting response calculations.