This is a grant to address problems related to polymeric and polymer matrix composite materials that have been identified as being key to the security of the U.S. The basic part of most polymer and composite materials manufacturing processes involves flow of polymers in cavities of arbitrary shape with or without reinforcement. Process throughput and product quality are often limited by the onset of flow instabilities. The existence of purely elastic instabilities suggest that all polymer processing operations, however slow they may be, are prone to instabilities. For this reason understanding the influence of fluid elasticity on flow and stability of representative bulk, free surface and interfacial flows is crucial. Fully parallelized, higher-order finite element techniques will be used to study a number of prototype two and three-dimensional free surface and interfacial flows of viscoelastic fluids. Specifically, the work will focus on investigating flow modifications due to fluid elasticity in mixed shearing/elongational flows as well as examining the role of fluid elasticity and non-equilibrium energetic effects on stability of this class of flows. Of particular interest is to identify the mechanism(s) that are responsible for viscoelastic instabilities in mixed kinematic flows which are routinely encountered in processing of polymers and composite materials.
