dc.contributor.author | Brasseur, E. | en |
dc.contributor.author | Fyrillas, Marios M. | en |
dc.contributor.author | Georgiou, Georgios C. | en |
dc.contributor.author | Crochet, M. J. | en |
dc.creator | Brasseur, E. | en |
dc.creator | Fyrillas, Marios M. | en |
dc.creator | Georgiou, Georgios C. | en |
dc.creator | Crochet, M. J. | en |
dc.date.accessioned | 2019-12-02T10:34:06Z | |
dc.date.available | 2019-12-02T10:34:06Z | |
dc.date.issued | 1998 | |
dc.identifier.uri | http://gnosis.library.ucy.ac.cy/handle/7/56546 | |
dc.description.abstract | We demonstrate that viscoelasticity combined with nonlinear slip acts as a storage of elastic energy generating oscillations of the pressure drop similar to those observed experimentally in extrusion instabilities. We consider the time-dependent axisymmetric incompressible Poiseuille and extrudate-swell flows of an Oldroyd-B fluid. We assume that slip occurs along the wall of the die following a slip equation which relates the shear stress to the velocity at the wall and exhibits a maximum and a minimum. We first study the stability of the one-dimensional axisymmetric Poiseuille flow by means of a one-dimensional linear stability analysis and time-dependent calculations. The numerically predicted instability regimes agree well with the linear stability ones. The calculations reveal that periodic solutions are obtained when an unstable steady-state is perturbed and that the amplitude and the period of the oscillations are increasing functions of the Weissenberg number. We then continue to numerically solve the time-dependent two-dimensional axisymmetric Poiseuille and extrudate-swell flows using the elastic-viscous split stress method for the integration of the constitutive equation. Again, oscillations are observed in the unstable regime | en |
dc.description.abstract | consequently, the surface of the extrudate is wavy. However, the amplitude and the period of the pressure drop oscillations are considerably smaller than in the one-dimensional flow. The most important phenomenon revealed by our two-dimensional calculations is that the flow in the die is periodic in the axial direction. © 1998 The Society of Rheology. | en |
dc.source | Journal of Rheology | en |
dc.source.uri | https://www.scopus.com/inward/record.uri?eid=2-s2.0-11644324069&partnerID=40&md5=4ea8de5c93bc77f22844c6596a2accda | |
dc.title | The time-dependent extrudate-swell problem of an Oldroyd-B fluid with slip along the wall | en |
dc.type | info:eu-repo/semantics/article | |
dc.description.volume | 42 | |
dc.description.issue | 3 | |
dc.description.startingpage | 549 | |
dc.description.endingpage | 566 | |
dc.author.faculty | Σχολή Θετικών και Εφαρμοσμένων Επιστημών / Faculty of Pure and Applied Sciences | |
dc.author.department | Τμήμα Μαθηματικών και Στατιστικής / Department of Mathematics and Statistics | |
dc.type.uhtype | Article | en |
dc.description.notes | <p>Cited By :34</p> | en |
dc.source.abbreviation | J.Rheol. | en |
dc.contributor.orcid | Fyrillas, Marios M. [0000-0003-3668-1648] | |
dc.contributor.orcid | Georgiou, Georgios C. [0000-0002-7451-224X] | |
dc.gnosis.orcid | 0000-0003-3668-1648 | |
dc.gnosis.orcid | 0000-0002-7451-224X | |