Periodic Fibre Suspension in a Viscoelastic Fluid - A Simulation by a Boundery Element Method

Abstract

This thesis presents some rheological problems of fibre suspensions in viscoelastic fluids. The completed double layer boundary element method was developed to simulate fibre suspensions in viscoelastic fluids. For dilute regime, a prolate spheroid rotating in shear flow of an Oldroyd-B fluid was simulated. Based on the simulated orbit of a prolate spheroid in viscoelastic shear flow, a constitutive model for the weakly viscoelastic fibre suspensions was proposed and its predictions were compared with some available numerical and experimental results. For non-dilute regime, formulation for periodic fibre suspensions in viscoelastic fluid was proposed. It is demonstrated that these equations are applicable for the simulation of multiple fibres suspended in viscoelastic shear flow. All simulated results are well compared to available experimental observations. This indicates that these numerical methods can be used in rheological research to provide useful information on the behaviour of fibre suspensions in viscoelastic fluids.