Characteristics of conical vortices and their effects on wind pressures on flat-roof-mounted solar arrays by LES

Abstract

Large eddy simulations (LES) are performed to examine the flow characteristics around solar arrays mounted on a flat-roof building for two oblique wind directions, 45° and 135°. The main purpose of this study is to clarify the mechanisms of some special features of wind pressure characteristics acting on solar panels obtained by wind tunnel experiments. Numerical simulation is first conducted for a flat-roof building without solar arrays to validate the accuracy of LES for oblique wind directions. Numerical simulations are then made for a flat-roof building with solar arrays. For 45° wind direction, local separations and reattachments of the downflows of the left-side conical vortex are found to play important roles in large negative pressures near the higher edges of the upper surfaces and positive pressures on some parts of the lower surfaces of solar panels. For 135° wind direction, local vortices generated from the higher edges of the solar panels form local wake regions downwind of the panels and cause downward net pressures on most of the panels. The effects of the gaps on pressures on the upper surfaces of solar arrays are not significant, but those on the lower surfaces are significant because of the flows passing under the panels.