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Engineering Mathematics
Review of Viscous Flows
Review of Computational Fluid Mechanics
Review of Turbulence and Turbulence Modeling

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The National Science Foundation
ME 637 The National Science Foundation
 Aerosols
Introduction to Aerosols | Drag, Lift Forces | Aerosol Kinetics | Virtual Mass, Basset Forces & BBO Equation | Nonspherical Particles | Brownian Motions | Particle Deposition Mechanisms | Electrodynamics | Aerosol Coagulation |

Lift Force

Lift Force on a Particle Touching a Plane

Leighton and Acrivos (1985) obtain the expression for the lift on the spherical particles resting on a plane substrate as shown in Figure 3. They found

(10)

Calculation Model

Lift Force

Lift Force


which is always pointing away from the wall. Note that the Saffman expression given by Equation 1 may be restated as

(11)

Equation 6 with IL given by Equation 7 reduces to Equation 10 for K=1,^G=-1.
For small particles in turbulent flows, using

(12)

where u* is the shear velocity, equations 10 and 11 become

(13)

(14)

where

(15)

Experimental studies of lift force were preformed for generally larger particles in the range of 100 to several hundred µm. Hall (1998) found

(16)

Mollinger and Nieuwstadt (1996) found

(17)

Figure 4 compares the model predictions with the experimental data of Hall. It is seen that the experimental data is generally much higher than the theoretical models.


Dr. Goodarz Ahmadi | Turbulence & Multiphase Fluid Flow Laboratory | Department of Mechanical & Aeronautical Engineering
Copyright © 2002-2005 Dr. Goodarz Ahmadi. All rights reserved.
Potsdam, New York, 13699
ahmadi@clarkson.edu