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...

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...

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...

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...

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 ...