LES study of wind pressure and flow characteristics of flat-roof-mounted solar arrays

Abstract

Wind loading is a major concern for solar array systems. To clarify the relations between flow field and wind pressure distributions on solar panels, large eddy simulations (LES) are performed to examine the flow characteristics around solar arrays mounted on a flat roof building for two normal wind directions, 0° and 180°. The mean, standard deviation and peak value of pressure and force coefficients obtained from LES and wind tunnel experiment are firstly compared to validate the accuracy of LES. Then the mean and unsteady flow fields around solar arrays are discussed to explain the corresponding wind pressure distributions. The local separation at the higher edges of solar panels located inside of both the separation bubble and the reattached flow are detected. The wind pressures on upper and lower surfaces of solar panels resulted by the local flow field are discussed accordingly for different scenarios. Ensemble-averaged flow fields on the condition of the occurrence of peak pressures at the higher edge of solar panels are also investigated. It is found that besides the large-scale separating and reattaching flow induced by the building, small-scale local separations at the higher edges of the solar panels are also responsible for the large peak of uplift.