Journal Title
Title of Journal: Environ Fluid Mech
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Abbravation: Environmental Fluid Mechanics
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Publisher
Springer Netherlands
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Authors: Robert Haehnel Nicole Buck Arnold Song
Publish Date: 2013/08/03
Volume: 14, Issue: 1, Pages: 135-156
Abstract
In wind tunnel experiments we study the effects of soil moisture on the threshold condition to entrain fine grain sand/silt into eolian flow and the nearbed concentration of airborne particles To study the effect of particle shape on moisture bonding we use two types of particles nearly equal in size spherical glass beads d 50 = 134upmu mathrmm and sieved quartz sand d 50 = 139 upmu mathrmm Both are poorly graded soils We conducted these experiments at low moisture contents 1 We found that the spherical particles were more sensitive to changes in moisture than the sand attributable to the large differences in specific surface area of the two particles The larger specific surface area for sand is due to the surface roughness of the angular sand particle Consequently sand “stores” more moisture via surface adsorption requiring higher soil moisture content to form liquid bridges between sand particles Based on these findings we extend the concept of a threshold moisture content wprime —originally proposed for clayey soils—to soils that lack any measureable clay content This allows application of existing models developed for clayey soils that quantify the moisture effect on the threshold friction velocity to sand and silty soils ie clay content = 0 Additionally we develop a model that quantifies the moisture effects on nearsurface airborne particulate concentration using experimental observations to determine the functional dependence on fluid and particle properties including soil specific area These models can be applied to numerical simulation of particulate plume formation and dispersion
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