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Simulation of Windbreaks for Wind-Erosion Control in a Wind Tunnel
W.M. Cornelis, D. Gabriels, and T. Lauwaerts
Abstract
Windbreaks have been used for many years to reduce wind speed as a wind-erosion control
measure. However, there is yet no clear answer on what should be the optimal design for
windbreaks. In a wind tunnel we tested five single-row barriers, each with different stem
and canopy porosity, and a two- and three-row barrier on their efficiency in wind-speed
reduction. Zones of erosion and deposition were determined from wind-speed measurements
and compared with experimental wind-tunnel data on sand transport. As regards porosity
distribution, evenly distributed porosity of stem and canopy resulted in the longest
protected area. Dense lower parts were more efficient than more porous lower parts. Two-
and three-row barriers were more efficient in terms of wind-speed reduction close to the
barrier only. At higher distances, single-row barriers resulted in higher wind-speed
reduction. Also sheltering zone of single-row barriers was higher. Erosion was almost not
observed in the case of a barrier with evenly distributed porosity. Deposition was only
significant in front of and up to 5 H leeward of such a barrier. The absence of a dense
lower part resulted in an excessive zone of erosion behind the barrier. The experimental
data confirmed the graphically determined zones of deposition. |
