Rheologica Acta, Vol.33, No.2, 136-144, 1994
FILM FLOW OF PSEUDOPLASTIC LIQUIDS ALONG AN OSCILLATING WALL
The film thickness of pseudoplastic liquids flowing down a vertical wall can be decreased by the longitudinal oscillations of the wall. This phenomenon is treated in the term of the flow enhancement which is common in the flows in oscillating tube. The theoretical predictions of the flow rate enhancement are reviewed for the boundary layer and creeping flow regimes. The experiments were done in the transient regime between these two asymptotic regimes. As high as five-fold decrease of the film thickness, which corresponds to the flow rate enhancements 10(5), was measured with concentrated kaolin suspensions with the flow index 0.15. Empirical correlations which describe the flow rate enhancement and the film thickness of the liquids with the power law viscosity function in the transient regime were found.
Keywords:VISCOELASTIC FLUIDS