In this talk, we present some joint work with current and former colleagues at Penn State (C. Liu, P. Yu and Y. Hyon) on moment closure approximations of multiscale complex fluid models. Moment closure not only provides a computationally feasible approach to simulate many multiscale phenomena but also offers insight to the understanding of the underlying physical processes. We will discuss some...

The FENE-P (Finitely-Extensible Nonlinear Elastic) dumbbell constitutive equation is widely used in simulations and stability analyses of free wall-bounded viscoelastic shear flows due to its relative simplicity accuracy predicting macroscopic properties dilute polymer solutions. model contains three independent material parameters, which expressed dimensionless form correspond a Weissenberg nu...

To explore the kinetics and morphology of flow induced crystallization of polymers, a nucleation-growth evolution model for spherulites and shish-kebabs is built based on Schneider rate model and Eder model. The model considers that the spherulites are thermally induced, growing like spheres, while the shish-kebabs are flow induced, growing like cylinders, with the first normal stress differenc...

Using a code developed to compute high Reynolds number viscoelastic flows, polymer injection from the upstream stagnation point of a circular cylinder is modeled at Re 1⁄4 3900. Polymer stresses are represented using the FENE-P constitutive equations. By increasing polymer injection rates within realistic ranges, significant near wake stabilization is observed. Rather than a turbulent detached ...

The Oldroyd-B fluid has become the starting point for almost all complex flow calculations and analysis involving behavior of dilute polymer solutions. reasons this are clear: based on kinetic theory high molecular weight “phantom” chains near equilibrium, resulting model, in its simplest form, produces a single mode description solution constitutive equation terms symmetric dyad order paramete...

Although the nonequilibrium behavior of polymer solutions is generally well understood, particularly in extensional flow, there remain several unanswered questions for dilute simple shear and full quantitative agreement with experiments has not been achieved. For example, experimental viscosity data exhibit qualitative differences shear-thinning exponents, rate onset shear-thinning, high-shear ...