Velocity overshoots in gradual contraction flows

• Type: Article in International Scientific Journal
• Date: 2009

Authors

Robert J Poole (Author) Other; Manuel A Alves (Author) FEUP

Journal

Title: Journal of Non-Newtonian Fluid Mechanics

Vol. 160 No. 1

Pages: 47-54

ISSN: 0377-0257

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 7 Citations

ISI Web of Science

Scopus - 9 Citations

COMPENDEX

INSPEC

Scientific classification

FOS: Engineering and technology > Mechanical engineering

Other information

Authenticus ID: P-003-HXF

DOI: 10.1016/j.jnnfm.2009.03.005

Abstract (EN): This study reports the results of a systematic numerical investigation, using the upper-convected Maxwell (UCM) and Phan-Thien-Tanner(PTT) models, of viscoelastic fluid flow through three-dimensional gradual planar contractions of various contraction ratios with the aim of investigating experimental observations of extremely large near-wall velocity overshoots in similar geometries [R.J. Poole, M.P. Escudier, P.J. Oliveira, Laminar flow of a viscoelastic shear-thinning liquid through a plane sudden expansion preceded by a gradual contraction, Proc. Roy. Soc. Lond. Set. A 461 (2005) 3827]. We are able to obtain good qualitative agreement with the experiments, even using the UCM model in creeping-flow conditions, showing that neither inertia, second normal-stress difference nor shear-thinning effects are required for the phenomenon to be observed. Guided by the numerical results we propose a simple explanation for the occurrence of the velocity overshoots and the conditions under which they arise.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8