Experiments of a sphere settling in simple shear flows of yield stress fluids

We present our preliminary experimental results on the flow induced by a settling sphere in a yield stress fluid with and without a cross shear flow. We investigate creeping flows and we use particle image velocimetry and particle tracking velocimetry to analyze the flow and measure the settling velocity. We show a breaking of the fore-aft symmetry in the direction of gravity and relate this to the rheological properties of the fluid. Also, we provide an estimation for the shear-induced sedimentation of an isolated sphere in a real yield stress fluid including elastic effects.