Windbreak Effectiveness for Storage Pile Fugitive Dust Control: A Wind Tunnel Study

Results of wind tunnel experiments to determine the optimal size and location of porous windbreaks for controlling fugitive dust emissions from storage piles in a simulated neutral atmospheric boundary layer are presented. Straight sections of windbreak material were placed upwind of two nonerodible, typically shaped piles and were also placed on the top of one of the piles. Wind speed near the pile surface is considered here as the primary factor affecting particle uptake. Wind speed distributions about the piles with and without porous windbreaks are presented. Relative wind speed reduction factors are described and efficiencies based on the relationship between wind speed and.particle uptake are given. The largest and most solid windbreak caused the greatest wind speed reduction, but similar wind speed reductions were also obtained from several smaller windbreaks. A 50 percent porous windbreak of height equal to the pile height and length equal to the pile length at the base, located one pile height from the base of the pile was found to be quite effective in reducing wind speeds over much of the pile. Windbreaks placed on the top of a flat-topped pile caused large wind speed reductions on the pile top, but small, if any, reductions on the windward pile face. Windbreak effectiveness decreased as the angle between the windbreak and the wind direction decreased