Surface tension driven jet break up of strain-hardening polymer solutions

Christanti, Yenny; Walker, Lynn M.

doi:10.1016/s0377-0257(01)00135-5

Cited by 175 publications

(158 citation statements)

References 37 publications

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“…3,4 The large viscoelastic stresses ensuing from this stretching can also result in the formation of a characteristic morphology known as a beadson-a-string structure, in which spherical fluid droplets are interconnected by long thin fluid ligaments. Understanding the distribution of the droplets resulting from the dynamics of this process is important in numerous commercial applications including jet breakup, 5 electrospinning, 6 and inkjet printing ͑for further details see the monograph by Yarin 7 ͒. Similar beads-on-a-string structures have also recently been documented in wormlike micellar solutions.…”

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confidence: 95%

“…5 The specific grade of polymer used ͑WSR-301͒ is commercially available and polydisperse, with a molecular weight M w Ϸ 3. show that the Deborah number in fluid threads of initial diameter 2r 0 Ϸ 1.2 mm is DeϷ 127. Eggers 15 notes that inertial, viscous, and capillary effects will all become important in a necking fluid thread ͑such that Ohϳ 1͒ on length scales ᐉ ϳ 0 2 / ͑ ͒.…”

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Iterated stretching and multiple beads-on-a-string phenomena in dilute solutions of highly extensible flexible polymers

2005

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A new instrument for dynamic helical squeeze flow which superposes oscillatory shear and oscillatory squeeze flow Rev. Sci. Instrum. 83, 085105 (2012) The effects of hydrodynamic interaction and inertia in determining the high-frequency dynamic modulus of a viscoelastic fluid with two-point passive microrheology Phys. Fluids 24, 073103 (2012) MHD free convection flow of a visco-elastic (Kuvshiniski type) dusty gas through a semi infinite plate moving with velocity decreasing exponentially with time and radiative heat transfer AIP Advances 1, 022132 (2011) Transitional flow of a non-Newtonian fluid in a pipe: Experimental evidence of weak turbulence induced by shearthinning behavior Phys. Fluids 22, 101701 (2010) Effects of viscoelasticity on the probability density functions in turbulent channel flow

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Iterated stretching and multiple beads-on-a-string phenomena in dilute solutions of highly extensible flexible polymers

2005

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“…At the time of pinch-off, the filament length for the Newtonian solvent is 1.4 cm compared to approximately 1 m for the polymer solution, given the same experimental conditions [44]. In other experimental settings, as the fluid elasticity was increased by increasing the polymer concentration or molecular weight, the rate of filament thinning decreased [2], the time to filament breakup increased [3], and the breakup length of jets increased [33,9]. These observations each illustrate the ability of viscoelasticity to enhance the stability of filaments to capillary breakup.…”

Section: Introductionmentioning

confidence: 99%

“…The dynamics of viscoelastic fluids are more complicated than that of Newtonian fluids since elastic (memory) and normal (forces perpendicular to the flow direction) effects can influence the flow, and the fluid properties themselves can vary with gradients in the flow. In extensional flows, the extensional viscosity is of importance [33,9]; for Newtonian fluids, it is three times the dynamic shear viscosity [49]. For viscoelastic fluids that strain-harden, the extensional viscosity can be up to 1000 times larger than the shear viscosity [47].…”

Section: Introductionmentioning

confidence: 99%

Exact solution for the extensional flow of a viscoelastic filament

et al. 2004

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We solve the free boundary problem for the dynamics of a cylindrical, axisymmetric viscoelastic filament stretching in a gravity-driven extensional flow for the Upper Convected Maxwell and Oldroyd-B constitutive models. Assuming the axial stress in the filament has a spatial dependence provides the simplest coupling of viscoelastic effects to the motion of the filament, and yields a closed system of ODEs with an exact solution for the stretch rate and filament thickness satisfied by both constitutive models. This viscoelastic solution, which is a generalization of the exact solution for Newtonian filaments, converges to the Newtonian power-law scaling as t → ∞. Based on the exact solution, we identify two regimes of dynamical behavior called the weakly-and strongly-viscoelastic limits. We compare the viscoelastic solution to measurements of the thinning filament that forms behind a falling drop for several semi-dilute (strongly-viscoelastic) polymer solutions. We find the exact solution correctly predicts the time-dependence of the filament diameter in all of the experiments. As t → ∞, observations of the filament thickness follow the Newtonian scaling 1/ √ t. The transition from viscoelastic to Newtonian scaling in the filament thickness is coupled to a stretch-to-coil transition of the polymer molecules.

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“…These sub-satellite droplets are estimated to be 16 to 60 μm in diameter and are believed to have formed during the breakup of long drawn-out filaments. [61,62] Ultimately, in designing a polymeric DCA the reduction in spray efficacy through the formation of oversized drops and the potential increase in sub-satellite droplets need to be taken into account. This should lead to an adjuvant which provides an optimal amount of elasticity to minimize drift and maximise spray efficacy.…”

Section: Agricultural Spraying Overviewmentioning

confidence: 99%

Polymeric Drift Control Adjuvants for Agricultural Spraying

Lewis

Evans

Malic

et al. 2016

Macro Chemistry & Physics

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---------The movement of a pesticide or herbicide to an off-target site during agricultural spraying can cause injury to wildlife, plants and contamination of surface water. This phenomenon is known as spray drift and can be controlled by spraying during favorable environmental conditions, and by using low drift nozzles and drift control adjuvants (DCAs). Polymeric DCAs are the most common type of DCA and function by increasing the droplet size produced during spraying. There are, however, two main drawbacks of polymeric DCAs; they are prone to mechanical degradation during spraying which reduces their performance and they can produce oversized drops which reduces the efficacy of the spray. In this review, existing DCA technology is reviewed including the mechanism through which they function.This then provides a platform for the discussion of novel polymeric architectures which have currently not been applied in DCA formulations.-2 -

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Surface tension driven jet break up of strain-hardening polymer solutions

Cited by 175 publications

References 37 publications

Iterated stretching and multiple beads-on-a-string phenomena in dilute solutions of highly extensible flexible polymers

Iterated stretching and multiple beads-on-a-string phenomena in dilute solutions of highly extensible flexible polymers

Exact solution for the extensional flow of a viscoelastic filament

Polymeric Drift Control Adjuvants for Agricultural Spraying

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