This article addresses the low Weissenberg asymptotic analysis (Newtonian limit) of some macroscopic models of viscoelastic fluid flows in the framework of global weak solutions. We investigate the convergence of the corotational Johnson-Segalman, the FENE-P, the Giesekus and PTT models. Relying on a priori bounds coming from energy or free energy estimates, we first study the weak convergence ...

Bu çalışmada okul dışı öğrenme ortamlarının, ilkokul dördüncü sınıf öğrencilerinin fene yönelik tutumlarına etkisinin araştırılması amaçlanmıştır. Araştırmada, iç içe karma desen kullanılmıştır. Çalışma grubu 2017-2018 eğitim-öğretim yılı içerisinde Kocaeli ili Gölcük ilçesindeki bir ilkokulda öğrenim gören 17 öğrencisinden oluşmaktadır. Araştırma kapsamında doğa eğitim gezisi ve Bilim Merkezin...

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 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...

Numerical simulations reveal the formation of singular structures in the polymer stress field of a viscoelastic fluid modeled by the Oldroyd-B equations driven by a simple body force. These singularities emerge exponentially in time at hyperbolic stagnation points in the flow and their algebraic structure depends critically on the Weissenberg number. Beyond a first critical Weissenberg number t...

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 ...

We study the existence of global-in-time weak solutions to a coupled microscopic-macroscopic bead-spring model which arises from the kinetic theory of dilute solutions of polymeric liquids with noninteracting polymer chains. The model consists of the unsteady incompressible Navier–Stokes equations in a bounded domain Ω ⊂ R, d = 2 or 3, for the velocity and the pressure of the fluid, with an ela...