Under this project we will develop predictive models of complex fluids, particularly wormlike micellar solutions and polymer fluids. As opposed to Newtonian fluids (such as water), these complex fluids exhibit shear-rate-dependent viscosities and elastic effects. Flows of these fluids exhibit purely elastic instabilities, pronounced thermal sensitivity, inhomogeneities in flow conditions (shear banding, shear induced structures, demixing), and early fracture. Mathematical models based on microstructural considerations will be developed consistent with two-fluid effects and with micellar breaking and reforming. The solutions of the resultant initial-boundary value problems for coupled systems of nonlinear partial differential equations with a non-local condition will be analyzed, numerically simulated, examined for stability characteristics, and compared with detailed experimental results in both shear and transient uniaxial extensional flows. The experiments will guide the modeling, and the modeling will in turn guide experimental measurements. The results of this research will form a basis for control of these fluids in use and in processing.
Polymer fluids and wormlike micellar solutions are ubiquitous today, being used in paints, plastics, foods, detergents, pharmaceuticals, agrochemical sprays, and oil recovery. A basic understanding of the properties of these mixtures under flow conditions is crucial to their effective use. Through a multidisciplinary collaboration, this project develops predictive tools for use in controlling flow of these complex fluids. This work has potential application as a predictive tool for an important sector of the economy.
