Alice Pelosse - Success and breakdown of Tanner's law with dense granular suspensions
Channel: The Hitchhiker's Guide To Rheology
Date: 2024-04-09

The spreading of viscous drops of density-matched suspensions on a solid surface is experimentally investigated at the global drop scale. The spreading dynamics still obeys Tanner’s law provided one uses an effective viscosity that happens to be smaller than the bulk viscosity of the suspension. Reasons for this decrease will be discussed and compared with the previous results of the effective viscosity at a more local scale when investigating the validity of Cox-Voinov's law with dense granular suspensions. Then, the late stage of the macroscopic behavior will be presented, when the height of the drop is of the order of the particle size. In this regime, Tanner’s law breaks down as the particles start to freeze and the pure fluid drains out of the solid matrix.