Understanding Rheology of Structured Fluids

Nearly all these materials have a viscosity that drops at higher rates of shear velocity resp, stress. This is the phenomenon of shear thinning which becomes progressively larger as the volume concentration of solid particles increases. At high concentration of solid content, the low shear rate viscosity region disappears completely, the material is yielding. Some materials show after the shear thinning region with increasing rate or stress, an increase of the viscosity, usually due to structure rearrangements as a result of the applied shear. This is referred to as flow induced shear thickening.