Mixing Of Complex Fluids: On The Effects Of Inhomogeneity

Abstract

We investigate the time evolution of mixing in a cylindrical container that is initially stably stratified. The bottom and top halves of the container are filled with Bingham and Newtonian fluids, respectively. The mixing is promoted by a rotating disk. We consider three different disk positions and illustrate that a non-negligible steady velocity magnitude is not a sufficient condition for effective local mixing. For the model problem considered, setting the disk mixer at the middle and top of the container leads to the shortest and longest mixing times, respectively.