### Session AP: Particle-Laden Flows I

8:30 AM–10:14 AM, Sunday, November 18, 2007
Salt Palace Convention Center Room: 251D

Chair: Rodney Fox, Iowa State University

Abstract ID: BAPS.2007.DFD.AP.6

### Abstract: AP.00006 : Gravity driven effect in flowing particle laden thin films

9:35 AM–9:48 AM

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#### Authors:

Robert Glidden
(UCLA)

Christopher Fox
(Harvey Mudd College)

Thomas Ward
(UCLA)

Andrea Bertozzi
(UCLA)

The flow characteristics of an anisopycnic particle-laden thin film flowing down an inclined plane is analyzed experimentally near the maximum packing limit for polydisperse hard spheres. The mutliphase fluid is a mixture of silicone oil and polydisperse heavy glass beads of varying viscosities and bead diameter, respectively. For the high volume concentrations studied, $50\% < \phi < 56\%$, we observe that the elapsed time, $t$, versus average front position, $x_N$, still scales with the Huppert solution where $C_N=x_N^3/t$ is a constant [Nature 300(2), 1982]. For very high background fluid viscosities, the particle settling velocity is very slow with respect to the fluid and $C_N$ decreases with increasing concentration. As the background fluid viscosity is decreased $C_N$ remains relatively constant as the particle density approaches the maximum. We propose that the latter effect may be the result of a transition from viscous fluid flow to that of a lubricated sliding solid body. Experiments are performed to test an empirical correlation for the data in this parameter regime based on this hypothesis.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.DFD.AP.6