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Instability of canopy flows
Author(s) -
Zampogna Giuseppe A.,
Pluvinage Franck,
Kourta Azeddine,
Bottaro Alessandro
Publication year - 2016
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2016wr018915
Subject(s) - canopy , instability , anisotropy , vortex , mechanics , drag coefficient , drag , flow (mathematics) , shear (geology) , geology , physics , optics , geography , petrology , archaeology
Abstract Honami and monami waves are caused by large‐scale coherent vortex structures which form in shear layers generated by canopies. In order to reach new insights on the onset of such waves, the instability of these shear layers is studied. Two different approaches are used. In the first approach, the presence of the canopy is modeled via a drag coefficient, taken to vary along the canopy as by experimental indications. The second approach considers the canopy as a porous medium and different governing equations for the fluid flow are deduced. In this second case, the anisotropy of the canopy, composed by rigid cylindrical elements, is accounted for via an apparent permeability tensor. The results obtained with the latter approach approximate better experimental correlations for the synchronous oscillations of the canopy.