dc.contributor.author | Georgiou, Georgios C. | en |
dc.creator | Georgiou, Georgios C. | en |
dc.date.accessioned | 2019-12-02T10:35:14Z | |
dc.date.available | 2019-12-02T10:35:14Z | |
dc.date.issued | 2003 | |
dc.identifier.uri | http://gnosis.library.ucy.ac.cy/handle/7/56849 | |
dc.description.abstract | We solve the time-dependent, compressible Poiseuille and extrudate-swell flows of a shear-thinning fluid that obeys the Carreau constitutive model, using finite elements in space and a fully-implicit scheme in time. Slip is assumed to occur along the die wall following a non-monotonic slip equation that relates the wall shear stress to the slip velocity and is based on experimental measurements with polyethylene melts. Thus, the resulting flow curve is also non-monotonic, and consists of two stable positive-slope branches and a linearly unstable negative-slope branch. The steady-state numerical results compare well with certain analytical solutions for Poiseuille flow. The time-dependent calculations at fixed volumetric flow rates demonstrate the existence of periodic solutions in the unstable regime, due to the combination of compressibility and slip. Self-sustained oscillations of the pressure-drop and of the mass-flow rate are obtained. In the extrudate region, high-frequency, small amplitude waves are generated on the free-surface, which also oscillates radially. The wavelength and the amplitude of the free-surface waves and the amplitude of the oscillations in the radial direction are reduced, as the Reynolds number is decreased and approaches the conditions of the experiments. r 2002 Elsevier Science B.V. All rights reserved. | en |
dc.source | Journal of Non-Newtonian Fluid Mechanics | en |
dc.source.uri | https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037321899&doi=10.1016%2fS0377-0257%2802%2900164-7&partnerID=40&md5=a1aef6dd56a3056c12deecdc1e1d05d4 | |
dc.subject | Mathematical models | en |
dc.subject | Stability | en |
dc.subject | Finite element method | en |
dc.subject | Compressibility | en |
dc.subject | Non Newtonian flow | en |
dc.subject | shear stress | en |
dc.subject | Polyethylenes | en |
dc.subject | Carreau model | en |
dc.subject | Extrudate-swell flow | en |
dc.subject | Slip | en |
dc.subject | Poiseuille flow | en |
dc.subject | Pressure drop | en |
dc.subject | Slip equations | en |
dc.subject | swell | en |
dc.subject | wall | en |
dc.title | The time-independent, compressible Poiseuille and extrudate-swell flows of a Carreau fluid with slip at the wall | en |
dc.type | info:eu-repo/semantics/article | |
dc.identifier.doi | 10.1016/S0377-0257(02)00164-7 | |
dc.description.volume | 109 | |
dc.description.issue | 2-3 | |
dc.description.startingpage | 93 | |
dc.description.endingpage | 114 | |
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 :42</p> | en |
dc.source.abbreviation | J.Non-Newton.Fluid Mech. | en |
dc.contributor.orcid | Georgiou, Georgios C. [0000-0002-7451-224X] | |
dc.gnosis.orcid | 0000-0002-7451-224X | |