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A joint velocity-intermittency analysis reveals similarity in the vertical structure of atmospheric and hydrospheric canopy turbulence

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journal contribution
posted on 06.08.2019, 08:15 by Chris KeylockChris Keylock, Marco Ghisalberti, Gabriel G Katul, Heidi M Nepf
Turbulent fow through and over vegetation continues to draw signifcant research attention given its relevance to a plethora of applications in earth and environmental science. Canopy fows are characterized by three-dimensional coherent vortical motions not directly accessible from single-point measurements, which pose a challenge to formalizing links between vegetation structure and turbulent motion. A joint velocity-intermittency technique is applied to velocity data collected within and above aquatic vegetation in a hydraulic fume and above a forested canopy. The approach reveals behavior that provides greater insight into canopy fow dynamics than may be inferred from the vertical profles of mean velocity, turbulence intensity and Reynolds stresses, which are the quantities usually studied. There is a remarkable similarity in the structure of such fows between the forest canopy and the fume study despite large diferences in morphology and stem rigidity. In particular, these results determine an outer fow type arising above 1.5 canopy heights, while turbulent in-rushing events are most signifcant at the zero-plane displacement. The approach also implies ways in which improved models for canopy turbulence may be developed.

History

School

  • Architecture, Building and Civil Engineering

Published in

Environmental Fluid Mechanics

Volume

20

Issue

1

Pages

77 - 101

Publisher

Springer Science and Business Media LLC

Version

VoR (Version of Record)

Rights holder

© The Authors

Publisher statement

This is an Open Access Article. It is published by Springer under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

Acceptance date

31/05/2019

Publication date

2019-07-04

Copyright date

2019

ISSN

1567-7419

eISSN

1573-1510

Language

en

Depositor

Prof Chris Keylock