Work

Droplet breakup in flow past an obstacle: A capillary instability due to permeability variations

Year: 2010

Type: article

Abstract: In multiphase flow in confined geometries an elementary event concerns the interaction of a droplet with an obstacle. As a model of this configuration we study the collision of a droplet with a circular post that spans a significant fraction of the cross-section of a microfluidic channel. We demonstrate that there exist conditions for which a drop moves completely around the obstacle without breaking, while for the same geometry but higher speeds the drop breaks. Therefore, we identify a critical value of the capillary number above which a drop will break. We explain the results with a one-dimensional model characterizing the flow in the narrow gaps on either side of the obstacle, which identifies a surface-tension–driven instability associated with a variation in the permeability in the flow direction. The model captures the major features of the experimental observations.

Source: Europhysics Letters (EPL)

DOI: 10.1209/0295-5075/92/54002

Authors: S. Protière, M. Z. Bazant, D. A. Weitz, H. A. Stone

Institutions: Harvard University, Massachusetts Institute of Technology, Princeton University

Language: English

Topic: Fluid Dynamics and Heat Transfer

Subfield: Computational Mechanics

Field: Engineering

Domain: Physical Sciences

Open Access status: bronze

Funders: Materials Research Science and Engineering Center, Harvard University, Division of Materials Research

Awards: G3646433677, G69416479