Wire mesh fences for manipulation of turbulence energy spectrum

A review of static and dynamic heliostat wind loads

“…Hence, the manipulation of inflow ABL turbulence by the fence and its effectiveness in wind load reduction were not reported. Turbulence properties downstream of mesh fences (Figure 27b) of various mesh opening widths and porosities were determined from experimental measurements in a wind tunnel (Jafari et al 2021). It was found that with application of fences with porosities between 0.46 and 0.75, an inflow streamwise turbulence intensity of 12.5% could be reduced to between 8.8% and 9.9%.…”

“…A disadvantage of such flow manipulator devices is the additional maintenance cost to clean the mirrors and the shading of the mirrors. a heliostat field perimeter porous wire mesh fence (Jafari et al 2021). The plots show the effect of wire mesh fence porosity on the predicted reduction of (c) the peak drag force/coefficient on a heliostat at 𝛼 = 90°, (d) the peak lift force/coefficient on a heliostat at 𝛼 = 0° (Jafari et al 2021).…”

“…Porous fences were found by Jafari et al (2021) to reduce the turbulence intensity and integral length scales by 20-25% relative to the incoming ABL, but the material cost of perimeter fences for large heliostats and their area of influence into a heliostat field remained a research question. Other methods to reduce the wind loads on heliostats positioned at the inner rows of a field include the attachment of "edge treatment" devices to the heliostat, such as to mitigate the impact of vortex shedding from the leading and trailing edges.…”