Shear-induced instabilities of flows through submerged vegetation

Clint Wong, Philippe Trinh, S. Jonathan Chapman

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1 Citation (Scopus)
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Abstract

We consider the instabilities of flows through a submerged canopy and show how the full governing equations of the fluid–structure interactions can be reduced to a compact framework that captures many key features of vegetative flow. First, by modelling the canopy as a collection of homogeneous elastic beams, we predict the steady configuration of the plants in response to a unidirectional flow. This treatment couples the beam equations in the canopy to the fluid momentum equations. Subsequently, a linear stability analysis suggests new insights into the development of instabilities at the surface of the vegetative region. In particular, we show that shear at the top of the canopy is a dominant factor in determining the onset of instabilities known as monami. Based on numerical and asymptotic analysis of the quadratic eigenvalue problem, the system is shown to be stable if the canopy is sufficiently sparse.
Original languageEnglish
Article numberA17
JournalJournal of Fluid Mechanics
Volume891
Early online date23 Mar 2020
DOIs
Publication statusPublished - 25 May 2020

Keywords

  • absolute/convective instability
  • coastal engineering
  • shear layers

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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