We present an enhanced moment-closure approximation to the finiteextensiblenonlinear-elastic (FENE) models of polymeric fluids. This new moment-closure method involves the perturbation of the equilibrium probability distribution function (PDF), which takes into account of the drastic split into two spikes and centralized behavior under the large macroscopic flow effects. The resulting macroscop...

In this paper, we propose an entropy satisfying conservative method to solve the Fokker-Planck equation of FENE dumbbell model for polymers, subject to homogeneous fluids. Both semi-discrete and fully discrete schemes satisfy all three desired properties: i) mass conservation, ii) positivity preserving, and iii) entropy satisfying in the sense that these schemes satisfy discrete entropy inequal...

A precision-machined cross-slot flow geometry with a shape that has been optimized by numerical simulation of the fluid kinematics is fabricated and used to measure the extensional viscosity of a dilute polymer solution. Full-field birefringence microscopy is used to monitor the evolution and growth of macromolecular anisotropy along the stagnation point streamline, and we observe the formation...

We revisit the rapid stretching of a liquid filament under the action of a constant imposed tensile force, a problem which was first considered by Matta & Tytus [JNNFM vol. 35, pp 215-229, 1990]. A liquid bridge formed from a viscous Newtonian fluid or from a dilute polymer solution is first established between two cylindrical disks. The upper disk is held fixed and may be connected to a force ...

It has been well-known for over six decades that the addition of minute amounts of long polymer chains to organic solvents, or water, can lead to significant turbulent drag reduction. This discovery has had many practical applications such as in pipeline fluid transport, oil well operations, vehicle design and submersible vehicle projectiles, and more recently arteriosclerosis treatment. Howeve...

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...

Polymer additives are commonly utilized to manipulate bubbly flows in various applications. Here, we investigate the effects of clean and contaminated bubbles driven upwards (upflow) Newtonian viscoelastic turbulent channel flows. Interface-resolved direct numerical simulations performed examine sole combined soluble surfactant viscoelasticity using an efficient 3D finite-difference/front-track...

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...