Drop dynamics of viscoelastic filaments

Pingulkar, Hrishikesh; Peixinho, Jorge; Crumeyrolle, Olivier

doi:10.1103/physrevfluids.5.011301

Cited by 10 publications

(13 citation statements)

References 41 publications

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“…By the same idea, we have estimated the relaxation time of the PEO solution as the inverse of the shear rate where η = 0.95η 0 , i.e., λ = λ C (0.95 −1/k − 1) −1/2 . Recently, Pingulkar et al [41] have measured the relaxation time of the PEO solutions for c = {200, 450, 600, 1000, 2000} ppm using capillary breakup extensional rheometer (CaBER). They have found that the relaxation time increases with increase in c of PEO following a power law : λ CaBER = 1.2c 0.83 .…”

Section: Relaxation Time Of Peomentioning

confidence: 99%

Transition to turbulence via flame patterns in viscoelastic Taylor–Couette flow

Latrache

Mutabazi

2021

Eur. Phys. J. E

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Transition to inertio-elastic turbulence in Taylor-Couette flow with shear-thinning and viscoelastic polymer solutions is investigated when the rotation rate of the inner cylinder is increased and the outer cylinder is fixed. In two polymer solutions of PEO with elastic number E ∈ {0.16; 0.30}, the first instability of the circular Couette flow appears as spirals propagating in opposite directions along the axis of cylinders. Just above the onset of the spirals pattern, the localized solitons of the strong radial inflow called flamelike flow appear abruptly inside waves. The abrupt apparition of the flame-like flow is the signature of the subcritical transition to turbulence. The number of the flame-like flows follows a Gaussian distribution at given Ta number. The averaged number of the flame-like flow increases as the rotation rate is increased and it saturates in the inertio-elastic turbulence. The soliton of the strong radial inflow (flame-pattern) is created when it amplitude exceeds a critical value. The distribution of the critical amplitudes of the flame patterns follows a Gaussian law at given Ta number. The transition to turbulence is described by a mathematical model based on an error function of the probability to observe a strong inflow (flame-pattern). The statistical data of the critical amplitude and the probability to observe the flame patterns are used with the mathematical model in order to determine the stability curve of the transition to turbulence. The analysis of the transition to turbulence is completed by the characterization of the spatiotemporal properties.

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Section: Relaxation Time Of Peomentioning

confidence: 99%

Transition to turbulence via flame patterns in viscoelastic Taylor–Couette flow

Latrache

Mutabazi

2021

Eur. Phys. J. E

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“…Further analysis of the diameter can be used to obtain the extensional viscosity as a function of time and Hencky strain. These results are given in Pingulkar et al 14 Based on the solution properties, several dimensionless numbers can be defined. The Deborah number, De = λ/τ R , represents a ratio of the viscoelastic time, λ, to the Rayleigh inertiocapillary time: τ R = ρR 0 3 /σ.…”

Section: Rheological Measurementsmentioning

confidence: 99%

“…For Newtonian fluids, during this liquid transfer, solution pools are formed on the end plates of a stretched liquid bridge. On the other hand, a stretched viscoelastic liquid bridge forms a persistent thin filament [9][10][11][12][13][14] along with the solution pools.…”

Section: Introductionmentioning

confidence: 99%

Liquid Transfer for Viscoelastic Solutions

Pingulkar,

Peixinho,

Crumeyrolle

2021

Preprint

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Viscoelastic liquid transfer from one surface to another is a process that finds applications in many technologies, primarily in printing. Here, cylindrical shaped capillary bridges pinned between two parallel disks are considered. Specifically, the effects of polymer mass fraction, solution viscosity, disk diameter, initial aspect ratio, final aspect ratio, stretching velocity and filling fraction (alike contact angle) are experimentally investigated in uniaxial extensional flow. Both Newtonian and viscoelastic polymer solutions are prepared using polyethylene glycol (PEG) and polyethylene oxide (PEO), with a wide variety of mass fractions. The results show that the increase in polymer mass fraction and solvent viscosity reduces the liquid transfer to the top surface. Moreover, the increase in the initial and final stretching height of the capillary bridge also decreases the liquid transfer, for both Newtonian and viscoelastic solutions. Finally, the shape of the capillary bridge is varied by changing the liquid volume. Now, Newtonian and viscoelastic solutions exhibit opposite behaviors for the liquid transfer. These findings are discussed in terms of interfacial shape instability and gravitational drainage.

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“…2010; Malkin, Arinstein & Kulichikhin 2014; Turkoz et al. 2018 b ; Pingulkar, Peixinho & Crumeyrolle 2020). Generally, more secondary droplets tend to be formed at smaller viscosities or smaller elasticities (Bhat et al.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of a viscoelastic thread surrounded by a Newtonian viscous fluid inside a cylindrical tube

2021

J. Fluid Mech.

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A viscoelastic thread in vacuum is known to evolve into a beads-on-a-string structure at large deformations. If the thread is immersed in another fluid, the surrounding medium may influence the topological structure of it, which remains unexplored. To get some insights into the nonlinear behaviour of a viscoelastic thread in a two-phase flow system, a one-dimensional model is developed under the slender body approximation, in which the thread of a highly viscoelastic fluid described by the Oldroyd-B or Giesekus constitutive equation is immersed in a Newtonian viscous fluid of much smaller density and viscosity inside a cylindrical tube. The effect of the outer viscous fluid layer and the confinement of the tube is examined. It is found that the outer fluid may change substantially the beads-on-a-string structure of the viscoelastic thread. Particularly, it may induce the formation of secondary droplets on the filament between adjacent primary droplets, even for large wavenumbers. The outer fluid exerts a resistance force on the extensional flow in the filament, but the necking of the thread is slightly accelerated, due to the redistribution of capillary and elastic forces along the filament accompanied by the formation of secondary droplets. Decreasing the tube radius leads to an increase in secondary droplet size but affects little the morphology of the thread. The non-uniformity of the filament between droplets is more pronounced for a Giesekus viscoelastic thread, and pinch-off of a Giesekus thread always occurs in the neck region connecting the filament to the primary droplet in the presence of the outer viscous fluid.

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Drop dynamics of viscoelastic filaments

Cited by 10 publications

References 41 publications

Transition to turbulence via flame patterns in viscoelastic Taylor–Couette flow

Transition to turbulence via flame patterns in viscoelastic Taylor–Couette flow

Liquid Transfer for Viscoelastic Solutions

Dynamics of a viscoelastic thread surrounded by a Newtonian viscous fluid inside a cylindrical tube

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