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dc.contributor.authorGhannam, Khaled
dc.contributor.authorBou-Zeid, Elie
dc.contributor.authorGerken, Tobias
dc.contributor.authorChamecki, Marcelo
dc.date.accessioned2019-02-08T19:02:52Z
dc.date.available2019-02-08T19:02:52Z
dc.date.issued2018-03
dc.identifier.citationGhannam, Khaled, Elie Bou-Zeid, Tobias Gerken, and Marcelo Chamecki. "Scaling and similarity of the anisotropic coherent eddies in near-surface atmospheric turbulence." Journal of the Atmospheric Sciences 75, no. 3 (March 2018). DOI:10.1175/JAS-D-17-0246.1.en_US
dc.identifier.issn0022-4928
dc.identifier.urihttps://scholarworks.montana.edu/xmlui/handle/1/15232
dc.description.abstractThe low-wavenumber regime of the spectrum of turbulence commensurate with Townsend's "attached" eddies is investigated here for the near-neutral atmospheric surface layer (ASL) and the roughness sublayer (RSL) above vegetation canopies. The central thesis corroborates the significance of the imbalance between local production and dissipation of turbulence kinetic energy (TKE) and canopy shear in challenging the classical distance-from-the-wall scaling of canonical turbulent boundary layers. Using five experimental datasets (two vegetation canopy RSL flows, two ASL flows, and one open-channel experiment), this paper explores (i) the existence of a low-wavenumber k-1 scaling law in the (wind) velocity spectra or, equivalently, a logarithmic scaling ln(r) in the velocity structure functions; (ii) phenomenological aspects of these anisotropic scales as a departure from homogeneous and isotropic scales; and (iii) the collapse of experimental data when plotted with different similarity coordinates. The results show that the extent of the k-1 and/or ln(r) scaling for the longitudinal velocity is shorter in the RSL above canopies than in the ASL because of smaller scale separation in the former. Conversely, these scaling laws are absent in the vertical velocity spectra except at large distances from the wall. The analysis reveals that the statistics of the velocity differences Δu and Δw approach a Gaussian-like behavior at large scales and that these eddies are responsible for momentum/energy production corroborated by large positive (negative) excursions in Δu accompanied by negative (positive) ones in Δw. A length scale based on TKE dissipation collapses the velocity structure functions at different heights better than the inertial length scale.en_US
dc.language.isoenen_US
dc.rightsThis Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-hoen_US
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en_US
dc.titleScaling and similarity of the anisotropic coherent eddies in near-surface atmospheric turbulenceen_US
dc.typeArticleen_US
mus.citation.issue3en_US
mus.citation.journaltitleJournal of the Atmospheric Sciencesen_US
mus.citation.volume75en_US
mus.identifier.categoryLife Sciences & Earth Sciencesen_US
mus.identifier.doi10.1175/JAS-D-17-0246.1en_US
mus.relation.collegeCollege of Agricultureen_US
mus.relation.departmentLand Resources & Environmental Sciences.en_US
mus.relation.universityMontana State University - Bozemanen_US
mus.data.thumbpage14en_US
mus.contributor.orcidGerken, Tobias|0000-0001-5617-186Xen_US


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