VISCOUS RESUSPENSION OF A SEDIMENT CAUSED BY OSCILLATING STRATIFIED FLOWS

It is known that a sediment of settled particles can resuspend under t he action of shear. In this paper, based on a mathematical model given by Leighton and Acrivos [6], we study theoretically the viscous resus pension of a sediment in a Couette channel with harmonically oscillati ng walls. Numerical experiments reveal that the resuspension height an d the particle volume concentration at the bottom of the channel depen d on the frequency of the oscillation. While oscillation of the top wa ll has nearly no influence on the sediment, a moving bottom wall cause s the settled particles to completely resuspend if the frequency is la rge enough.