Bulk flow driven by a viscous monolayer

Aditya Raghunandan, Juan Lopez, Amir H. Hirsa

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

The flow in the bulk driven by a viscous interfacial film set in motion by a rotating sharp circular knife edge has been examined through experiments and computations. In the experiments, the water surface is covered by an insoluble monomolecular film of dipalmitoylphosphatidylcholine (DPPC), a molecule of wide interest in biology and medicine. It is shown that the viscous coupling between the interfacial film and the bulk liquid leads to a strong bulk flow. Depending on the surface packing and corresponding surface tension, DPPC monolayers exhibit a wide range of phase morphologies. Upon shearing the monolayer, its viscous response varies from that of an essentially inviscid film at low surface packing, to that of a highly viscous non-Newtonian (shear thinning) film when the packing is dense. The more viscous the film, the stronger the driven bulk flow. We have examined this behaviour for hydrodynamic regimes straddling the Stokes flow regime and where flow inertia is important.

Original languageEnglish (US)
Pages (from-to)283-300
Number of pages18
JournalJournal of Fluid Mechanics
Volume785
DOIs
StatePublished - Nov 23 2015

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Keywords

  • biological fluid dynamics
  • interfacial flows (free surface)

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Condensed Matter Physics

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