A very stiff finitely extensible nonlinear elastic (FENE)-Fraenkel spring is proposed to replace the rigid rod in the bead-rod model. This allows the adoption of a fast predictor-corrector method so that large time steps can be taken in Brownian dynamics (BD) simulations without over- or understretching the stiff springs. In contrast to the simple bead-rod model, BD simulations with beads and F...

The dynamics of drop formation and pinch-off have been investigated for a series of low viscosity elastic fluids possessing similar shear viscosities, but differing substantially in elastic properties. On initial approach to the pinch region, the viscoelastic fluids all exhibit the same global necking behaviour that is observed for a Newtonian fluid of equivalent shear viscosity. For these low ...

We prove global well-posedness for the microscopic FENE model under a sharp boundary requirement. The well-posedness of the FENE model that consists of the incompressible Navier-Stokes equation and the Fokker-Planck equation has been studied intensively, mostly with the natural flux boundary condition. Recently it was illustrated by C. Liu and H. Liu [2008, SIAM J. Appl. Math., 68(5):1304–1315]...

Senile plaques (SPs) and neurofibrillary tangles (NFTs) are hallmark pathologies accompanying the neurodegeneration involved in Alzheimer's disease (AD), for which beta-amyloid (Abeta) peptide is a major constituent of SPs. Our laboratories previously developed the hydrophobic, fluorescent molecular-imaging probe 2-(1-(6-[(2-[(18)F]fluoroethyl)(methyl)amino]-2-naphthyl)ethylidene)malononitrile ...

Direct numerical simulations are carried out to study the effect of finite Weissenberg number up $Wi=16$ on laminar and turbulent channel flows an elastoviscoplastic (EVP) fluid, at a fixed bulk Reynolds $2800$ . The incompressible flow equations coupled with evolution equation for EVP stress tensor by modified Saramito model that extends both Bingham viscoplastic extensible nonlinear elastic-P...

Abstract We report a unique tuneable analogue trend in particle focusing the laminar and weak viscoelastic regime of elasto-inertial flows. observe experimentally that particles circular cross-section microchannels can be tuned to any bandwidths lie between “Segre-Silberberg annulus” centre microcapillary. use direct numerical simulations investigate this phenomenon understand how minute amount...

The recently discovered centre-mode instability of rectilinear viscoelastic shear flow (Garg et al. , Phys. Rev. Lett. vol. 121, 2018, 024502) has offered an explanation for the origin elasto-inertial turbulence that occurs at lower Weissenberg numbers ( $Wi$ ). In support this, we show using weakly nonlinear analysis subcriticality found in Page 125, 2020, 154501) is generic across neutral cur...

We present a new closure for the mean rate of stretching of a dissolved polymer by homogeneous isotropic turbulence. The polymer is modeled by a bead-spring-type model (e.g., Oldroyd B, FENE-P, Giesekus) and the analytical closure is obtained assuming the Lagrangian velocity gradient can be modeled as a Gaussian, white-noise stochastic process. The resulting closure for the mean stretching depe...