Vortex shedding in cylinder flow of shear-thinning fluids. III - Pressure measurement

• Type: Article in International Scientific Journal
• Date: 2004

Authors

Paulo M. Coelho (Author) FEUP; Fernando Tavares Pinho (Author) FEUP

Journal

Title: Journal of Non-Newtonian Fluid Mechanics

Vol. 121 No. 1

Pages: 55-68

ISSN: 0377-0257

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 36 Citations

Scopus - 47 Citations

Other information

Authenticus ID: P-000-97S

DOI: 10.1016/j.jnnfm.2004.04.004

Abstract (EN): Measurements of pressure on the cylinder surface for the flow of Newtonian and non-Newtonian fluids around a circular cylinder were carried out, from which several parameters were calculated: the form drag coefficient (C-D), the pressure rise coefficient (C-pb - C-pm) and the wake angle (theta(w)). The non-Newtonian fluids were aqueous solutions of CMC and tylose with varying degrees of shear-thinning and elasticity, at weight concentrations of 0.1-0.6% and the experiments encompassed the transition and shear-layer transition regimes. For low Reynolds numbers flows elasticity on the shear layers was responsible for an increase in drag reduction with polymer concentration. Within the shear-layer transition regime the increase of the wake angle and pressure rise coefficient for the more concentrated solutions reduced CD by narrowing the near wake. For the tylose solutions a good correlation was found between the elasticity number and the mean pressure rise coefficient.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14