Fascinating rheological properties like shear thickening/thinning and anisotropic viscosity arise from underlying structure in complex fluids. We develop and use techniques to simultaneously analyze emergent, large-scale properties and image particle-level positions and stresses in such suspensions.
Understanding the flow of complex fluids through confined spaces and forces governing the flow is key to diverse fields, from blood flow to lubricant design. Studying such situations is difficult because typical devices cannot achieve the necessary degree of confinement. New experiments and simulations reveal flow behavior under different levels of confinement and show how this behavior can be tuned.
How Confinement-Induced Structures Alter the Contribution of Hydrodynamic and Short-Ranged Repulsion Forces to the Viscosity of Colloidal Suspensions
When you mix cornstarch and water you get an unusual result. If you treat it gently, it behaves like a liquid. But if you are rough with it, it behaves like a solid. How can this be? Itai Cohen, associate professor of physics, and his graduate student, Neil Lin, demonstrate the phenomenon and explain the reasons behind it.