Suspensions of Noncolloidal Particles in Yield Stress Fluids: Experimental and Micromechanical Approaches

Abstract

We study experimentally and theoretically the behavior of suspensions of noncolloidal particles in yield stress fluids. We develop procedures and materials that allow focusing on the purely mechanical contribution of the particles to the yield stress fiuid behavior, allowing relating the macroscopic properties of these suspensions to the mechanical properties of the yield stress fluid and the particle volume fraction. We find that the elastic modulus/concentration relationship follows a Krieger‐Dougherty law, and show that the yield stress/concentration relationship is related to the elastic modulus/concentration relationship through a very simple law, in agreement with a micromechanical analysis. We finally present evidence for shear‐induced migration in the flows of these suspensions.