Particle Resuspension in Turbulent Flow: A Stochastic Model for Individual Soil Grains

Figures & data

FIG. 1 Force balance acting on a single soil particle subject to aerodynamic and adhesive forces (adapted from Greeley and Iversen, 1985).

FIG. 2 The lift force acting on a non-rotating particle over a range of Reynolds numbers. The lift force has been non-dimensionalized as F_L|*bsup*| + |*esup*| = F_L/ν | *bsup*| 2| *esup*| ρ where F_L| *bsup*| +| *esup*| is the dimensionless lift force, F_L is the dimensional lift force, and ρ is the density of the fluid taken here to be 1.225 kg m| *bsup*| -3|*esup*|. Equations for the lift force as functions of Re are represented as lines. Tabular data for the lift force are represented by discrete points.

TABLE 1 The Lifshitz-van der Waals constants for lead and common soil minerals (Tsai et al., 1991)

Material	h(ergs)
Lead	2.140 × 10^− 12
Mica	1.000 × 10^− 12
SiO2	8.530 × 10^− 13

FIG. 3 The relative contribution of forces acting on a particle at rest at u* = 1.0 m/s.

FIG. 4 The threshold friction velocity for particle resuspension. Note that resuspension can occur well below these threshold friction velocities as a result of random turbulent fluctuations.

FIG. 5 The position of a particle entrained in a u* = 0.8 m/s flow over 1.4 seconds.

FIG. 7 The instantaneous horizontal, u, and vertical, w, wind velocities and the horizontal, u|*bsub*|p|*esub*|, and vertical, w|*bsub*|p|*esub*|, velocities for a 75 μ m particle at u* = 0.8 m/s.

FIG. 8 The instantaneous horizontal, u, and vertical, w, wind velocities and the horizontal, u|*bsub*|p|*esub*|, and vertical, w|*bsub*|p|*esub*|, velocities for a 1 μ m particle at u* = 0.5 m/s.

FIG. 6 The position of a 10 μ m particle entrained in various flow rates over 0.88 seconds.

FIG. 9 The horizontal distance traveled by particles of various diameters over 0.176 seconds at u* = 0.75 m/s. The ends of the box denote the first and third quartiles of the model results. Lines extend to the 5th and 95th percentiles. The median value is shown with a circle. The mean is shown by a cross.

FIG. 10 The horizontal distance traveled by particles of various diameters over 0.176 seconds at u* = 0.50 m/s. The ends of the box denote the first and third quartiles of the model results. Lines extend to the 5th and 95th percentiles. The median value is shown with a circle. The mean is shown by a cross.

FIG. 11 The vertical distance traveled by particles of various diameters over 0.176 seconds at u* = 0.75 m/s. The ends of the box denote the first and third quartiles of the model results. Lines extend to the 5th and 95th percentiles. The median value is shown with a circle. The mean is shown by a cross.

FIG. 12 The vertical distance traveled by particles of various diameters over 0.176 seconds at u* = 0.50 m/s. The ends of the box denote the first and third quartiles of the model results. Lines extend to the 5th and 95th percentiles. The median value is shown with a circle. The mean is shown by a cross.

FIG. 13 The horizontal distance traveled by a 1 μ m particle over 0.65 seconds at various friction velocities. The ends of the box denote the first and third quartiles of the model results. Lines extend to the 5th and 95th percentiles. The median value is shown with a circle. The mean is shown by a cross.

FIG. 14 The horizontal distance traveled by a 10 μ m particle over 0.65 seconds at various friction velocities. The ends of the box denote the first and third quartiles of the model results. Lines extend to the 5th and 95th percentiles. The median value is shown with a circle. The mean is shown by a cross.

FIG. 15 The vertical distance traveled by a 1 μ m particle over 0.65 seconds at various friction velocities. The ends of the box denote the first and third quartiles of the model results. Lines extend to the 5th and 95th percentiles. The median value is shown with a circle. The mean is shown by a cross.

FIG. 16 The vertical distance traveled by a 10 μ m particle over 0.65 seconds at various friction velocities. The ends of the box denote the first and third quartiles of the model results. Lines extend to the 5th and 95th percentiles. The median value is shown with a circle. The mean is shown by a cross.

Greeley , R. and Iversen , J. D. 1985 . Physics of Particle Motion , New York : Cambridge University Press .

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Tsai , C. -J. , Pui , D. Y. H. and Liu , B. Y. H. 1991 . Elastic Flattening and Particle Adhesion . Aerosol Science and Technology , 15 : 239 – 255 .

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