Viscoelastic instabilities in micro-scale flows

• Type: Article in International Scientific Journal
• Date: 2014

Authors

Francisco J. Galindo-Rosales (Author) FEUP; Laura Campo-Deaño (Author) FEUP; Patrícia C. Sousa (Author) FEUP; Vera M. Ribeiro (Author) FEUP; Mónica S. N. Oliveira (Author) FEUP; Manuel A. Alves (Author) FEUP; Fernando T. Pinho (Author) FEUP

Journal

Title: Experimental Thermal and Fluid Science

Vol. 59

Pages: 128-139

ISSN: 0894-1777

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 17 Citations

ISI Web of Science

Scopus - 38 Citations

Scientific classification

FOS: Engineering and technology

Associated Projects

ANEURYSM - ANEURYSM - Estudo Hemodinâmico em Aneurismas Cerebrais

MICROMIXING - Sistemas passivos de mistura em microgeometrias para escoamentos de fluidos viscoelásticos

Other information

Authenticus ID: P-009-XTS

DOI: 10.1016/j.expthermflusci.2014.03.004

Abstract (EN): Many artificial and natural fluids contain macromolecules, particles or droplets that impart complex flow behavior to the fluid. This complex behavior results in a non-linear relationship between stress and deformation standing in between Newton’s law of viscosity for an ideal viscous liquid and Hooke’s law for an ideal elastic material. Such non-linear viscoelastic behavior breaks down flow reversibility under creeping flow conditions, as encountered at the micro-scale, and can lead to flow instabilities. These instabilities offer an alternative to the development of systems requiring unstable flows under conditions where chaotic advection is unfeasible. Flows of viscoelastic fluids are characterized by the Weissenberg (Wi) and Reynolds (Re) numbers, and at the micro-scale flow instabilities occur in regions in the Wi–Re space typically unreachable at the macro-scale, namely high Wi and low Re. In this paper, we review recent experimental work by the authors on the topic of elastic instabilities in flows having a strong extensional component, including: flow through a hyperbolic contraction followed by a sudden expansion; flow in a microfluidic diode and in a flow focusing device; flow around a confined cylinder; flow through porous media and simplified porous media analogs. These flows exhibit different types of flow transitions depending on geometry, Wi and Re, including: transition from a steady symmetric to a steady asymmetric flow, often followed by a second transition to unsteady flow at high Wi; direct transition between steady symmetric and unsteady flows.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12