In this paper we present a reduced basis method for the parametrized Fokker–Planck equation associated with evolution of Finitely Extensible Nonlinear Elastic (FENE) dumbbells in a Newtonian solvent for a (prescribed) extensional macroscale flow. There are two new important ingredients: a projection–based POD–Greedy sampling procedure for the stable identification of optimal reduced basis space...

The flow of viscoelastic liquids with constant shear viscosity through symmetric sudden expansions is studied by numerical means. The geometry considered is planar and the constitutive model follows the modified FENE-CR equation, valid for relative dilute solutions of polymeric fluids. For Newtonian liquids in a 1:3 expansion we predict the result that the flow becomes asymmetric for a Reynolds...

We present a new finite-difference formulation to update the conformation tensor in dumbbell models (e.g., Oldroyd-B, FENE-P, Giesekus) that guarantees positive eigenvalues of the tensor (i.e., the tensor remains positive definite) and prevents over-extension for finite-extensible models. The formulation is a generalization of the second-order, central difference scheme developed by Kurganov an...

The effects of stiffness on the diffusion-limited dynamics of dumbbells in solution is studied numerically. The Langevin equation is used with two different models, the so-called Fraenkel and FENE dumbbells. It is found that the dynamics of rotation and stretching are dictated by the two following trends: (i) the density-density correlation function for these modes decays more slowly for larger...

We examine, with asymptotic analysis and numerical simulation, the iterated stretching dynamics of FENE and Oldroyd-B jets of initial radius r0 , shear viscosity n, Weissenberg number We, retardation number S, and capillary number Ca. The usual Rayleigh instability stretches the local uniaxial extensional flow region near a minimum in jet radius into a primary filament of radius @Ca(12S)/We#r0 ...

مکانیزم شکست ناشی از خزش در طی حادثه شدید یک رآکتور‌ آبی‌تحت‌فشار به‌جهت انتقال مواد رادیواکتیو به محیط‌زیست اهمیت ویژه‌ای برخوردار است. دنبال شدید، حرارت واپاشی منتقل‌شده سایر قسمت‌های سیستم‌خنک‌کننده رآکتور می‌تواند منجر گرم‌شدن سازه‌های سیستم خنک‌کننده (RCS) و خرابی نواحی تحت‌فشار آسیب‌پذیر شود. قطع‌کامل‌برق (SBO) بدون اقدامات اپراتور (توالی TMLB) یکی محتمل‌ترین سناریوهایی است که ممکن یکپارچ...