Flow and motion behavior of particle suspensions in shear flow over a rough surface

The paper discloses the experimental study results of the behavior of a thin layer of low concentrated slurry in a shear flow over a rough surface with a defined structure of the bottom wall. A new ring shear device was built which contains an optically transparent test chamber of which the bottom wall contains arrays of micro-cantilever force sensors simulating a defined surface roughness. It was created by deep-etching of micro-pillars in a silicon wafer. The results of visual observation of the interaction of the suspension with the structured surface during severe deformation are shown. Observation covered the liquid phase motion by micro-PIV, the interaction between the liquid phase and solid particles, the movement of separate particles and their mutual interaction. The contact interactions between particles and micro-pillars are exemplified. The abrupt changes in rotational motion and translational velocity of particles induce mutual collisions and continuous formation and break-up of cluster structures of various types