Three-dimensional streaming Flow in confined geometries

Bhargav Rallabandi, Alvaro Marin, Massimiliano Rossi, Christian J. Kähler, Sascha Hilgenfeldt

Research output: Contribution to journalArticle

Abstract

Steady streaming vortex flow from microbubbles has been developed into a versatile tool for microfluidic sample manipulation. For ease of manufacture and quantitative control, set-ups have focused on approximately two-dimensional flow geometries based on semi-cylindrical bubbles. The present work demonstrates how the necessary flow confinement perpendicular to the cylinder axis gives rise to non-trivial three-dimensional flow components. This is an important effect in applications such as sorting and micromixing. Using asymptotic theory and numerical integration of fluid trajectories, it is shown that the two-dimensional flow dynamics is modified in two ways: (i) the vortex motion is punctuated by bursts of strong axial displacement near the bubble, on time scales smaller than the vortex period; and (ii) the vortex trajectories drift over time scales much longer than the vortex period, forcing fluid particles onto three-dimensional paths of toroidal topology. Both effects are verified experimentally by quantitative comparison with astigmatism particle tracking velocimetry (APTV) measurements of streaming flows. It is further shown that the long-time flow patterns obey a Hamiltonian description that is applicable to general confined Stokes flows beyond microstreaming.

Original languageEnglish (US)
Pages (from-to)408-429
Number of pages22
JournalJournal of Fluid Mechanics
Volume777
DOIs
StatePublished - Jan 1 2015

Fingerprint

Vortex flow
vortices
Geometry
geometry
two dimensional flow
bubbles
Trajectories
trajectories
Confined flow
flow geometry
Hamiltonians
Stokes flow
three dimensional flow
astigmatism
Fluids
fluids
classifying
numerical integration
Sorting
Microfluidics

Keywords

  • Bubble dynamics
  • Low-Reynolds-number flows
  • Microfluidics

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Three-dimensional streaming Flow in confined geometries. / Rallabandi, Bhargav; Marin, Alvaro; Rossi, Massimiliano; Kähler, Christian J.; Hilgenfeldt, Sascha.

In: Journal of Fluid Mechanics, Vol. 777, 01.01.2015, p. 408-429.

Research output: Contribution to journalArticle

Rallabandi, Bhargav ; Marin, Alvaro ; Rossi, Massimiliano ; Kähler, Christian J. ; Hilgenfeldt, Sascha. / Three-dimensional streaming Flow in confined geometries. In: Journal of Fluid Mechanics. 2015 ; Vol. 777. pp. 408-429.
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