Numerical simulation of contraction and expansion flows of Langmuir monolayers

Mitsoulis, E; Argyropaidas, I

dc.contributor.author	Mitsoulis, E	en
dc.contributor.author	Argyropaidas, I	en
dc.date.accessioned	2014-03-01T01:31:27Z
dc.date.available	2014-03-01T01:31:27Z
dc.date.issued	2009	en
dc.identifier.issn	0377-0257	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/19800
dc.subject	Contraction flows	en
dc.subject	Expansion flows	en
dc.subject	Integral constitutive equations	en
dc.subject	Langmuir monolayers	en
dc.subject	Olley model	en
dc.subject	Planar extensional viscosity	en
dc.subject	Vortex formation	en
dc.subject.classification	Mechanics	en
dc.subject.other	Air	en
dc.subject.other	Electron energy levels	en
dc.subject.other	Expansion	en
dc.subject.other	Fluid dynamics	en
dc.subject.other	Hardening	en
dc.subject.other	Monolayers	en
dc.subject.other	Phase interfaces	en
dc.subject.other	Shrinkage	en
dc.subject.other	Viscosity	en
dc.subject.other	Vortex flow	en
dc.subject.other	Contraction flows	en
dc.subject.other	Expansion flows	en
dc.subject.other	Integral constitutive equations	en
dc.subject.other	Langmuir monolayers	en
dc.subject.other	Olley model	en
dc.subject.other	Planar extensional viscosity	en
dc.subject.other	Vortex formation	en
dc.subject.other	Constitutive equations	en
dc.title	Numerical simulation of contraction and expansion flows of Langmuir monolayers	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.jnnfm.2008.10.007	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.jnnfm.2008.10.007	en
heal.language	English	en
heal.publicationDate	2009	en
heal.abstract	Langmuir monolayers consist of amphiphilic molecules at the air-water interface and can be modeled as two-dimensional fluids. Earlier experiments [D.J. Olson, G.G. Fuller, J. Non-Newtonian Fluid Mech. 89 (2000) 187-207] on 4:1 contraction and 4:1 expansion flows have been simulated using an integral constitutive equation of the K-BKZ type, suitably modified to account for strain-thickening in the planar extensional viscosity. The model has been used to fit linear viscoelastic data (G' and G '') and the shear viscosity (eta(S)), while the amount of strain-hardening is assumed, due to lack of experimental data. The simulations are in good agreement with the experiments on Newtonian monolayers. which show no vortices in the contraction but large inertial vortices in the expansion. For the viscoelastic monolayer (a poly-octadecyl methacrylate or PODMA), the opposite is true. The contraction flow shows vortices, while in the expansion flow the Vortex activity is substantially reduced compared with the Newtonian one. The viscoelastic behavior is well captured by the model, provided that Substantial strain-thickening is exhibited by the monolayer in planar extension. The latter behavior is very much like that for a branched LDPE melt, which also shows big vortices due to strain-hardening in planar as well as in uniaxial extension. (C) 2008 Elsevier B.V. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	Journal of Non-Newtonian Fluid Mechanics	en
dc.identifier.doi	10.1016/j.jnnfm.2008.10.007	en
dc.identifier.isi	ISI:000264250300007	en
dc.identifier.volume	157	en
dc.identifier.issue	3	en
dc.identifier.spage	163	en
dc.identifier.epage	174	en