Purely elastic instabilities in three-dimensional cross-slot geometries

• Type: Article in International Scientific Journal
• Date: 2010

Authors

A. M. Afonso (Author) Other; M. A. Alves (Author) FEUP; F. T. Pinho (Author) FEUP

Journal

Title: Journal of Non-Newtonian Fluid Mechanics

Vol. 165 No. 13-14

Pages: 743-751

ISSN: 0377-0257

Publisher: Elsevier

Indexing

ISI Proceedings

ISI Web of Knowledge - 20 Citations

ISI Web of Science

Scopus - 24 Citations

INSPEC

COMPENDEX

Scientific classification

FOS: Engineering and technology > Mechanical engineering

Other information

Authenticus ID: P-003-5BN

DOI: 10.1016/j.jnnfm.2010.03.010

Abstract (EN): Creeping and low Reynolds number flows of an upper-convected Maxwell (UCM) fluid are investigated numerically in a three-dimensional orthogonal cross-slot geometry. We analyze two different flow configurations corresponding to uniaxial extension and biaxial extension, and assess the effects of extensional flow type, Deborah and Reynolds numbers on flow dynamics near the interior stagnation point. Using these two flow arrangements the amount of stretch and compression near the stagnation point can be varied. providing further insights on the viscoelastic flow instability mechanisms in extensionally dominated flows with an interior stagnation point. The uniaxial extensional flow arrangement leads to the onset of a steady flow asymmetry, followed by a second purely elastic flow instability that generates an unsteady flow at higher flow rates. On the other hand, for the biaxial extension flow configuration a symmetric How is observed up to the critical Deborah number when the time-dependent purely elastic instability sets in, without going through the steady symmetric to steady asymmetric transition.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9