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Wind-Tunnel Simulation of Weakly and Moderately Stable Atmospheric Boundary Layers

The simulation of horizontally homogeneous boundary layers that have characteristics of weakly and moderately stable atmospheric flow is investigated, where the well-established wind engineering practice of using ‘flow generators’ to provide a deep boundary layer is employed. Primary attention is gi...

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Detalles Bibliográficos
Autores principales: Hancock, Philip E., Hayden, Paul
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Netherlands 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6438612/
https://www.ncbi.nlm.nih.gov/pubmed/30996390
http://dx.doi.org/10.1007/s10546-018-0337-7
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author Hancock, Philip E.
Hayden, Paul
author_facet Hancock, Philip E.
Hayden, Paul
author_sort Hancock, Philip E.
collection PubMed
description The simulation of horizontally homogeneous boundary layers that have characteristics of weakly and moderately stable atmospheric flow is investigated, where the well-established wind engineering practice of using ‘flow generators’ to provide a deep boundary layer is employed. Primary attention is given to the flow above the surface layer, in the absence of an overlying inversion, as assessed from first- and second-order moments of velocity and temperature. A uniform inlet temperature profile ahead of a deep layer, allowing initially neutral flow, results in the upper part of the boundary layer remaining neutral. A non-uniform inlet temperature profile is required but needs careful specification if odd characteristics are to be avoided, attributed to long-lasting effects inherent of stability, and to a reduced level of turbulent mixing. The first part of the wind-tunnel floor must not be cooled if turbulence quantities are to vary smoothly with height. Closely horizontally homogeneous flow is demonstrated, where profiles are comparable or closely comparable with atmospheric data in terms of local similarity and functions of normalized height. The ratio of boundary-layer height to surface Obukhov length, and the surface heat flux, are functions of the bulk Richardson number, independent of horizontal homogeneity. Surface heat flux rises to a maximum and then decreases.
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spelling pubmed-64386122019-04-15 Wind-Tunnel Simulation of Weakly and Moderately Stable Atmospheric Boundary Layers Hancock, Philip E. Hayden, Paul Boundary Layer Meteorol Research Article The simulation of horizontally homogeneous boundary layers that have characteristics of weakly and moderately stable atmospheric flow is investigated, where the well-established wind engineering practice of using ‘flow generators’ to provide a deep boundary layer is employed. Primary attention is given to the flow above the surface layer, in the absence of an overlying inversion, as assessed from first- and second-order moments of velocity and temperature. A uniform inlet temperature profile ahead of a deep layer, allowing initially neutral flow, results in the upper part of the boundary layer remaining neutral. A non-uniform inlet temperature profile is required but needs careful specification if odd characteristics are to be avoided, attributed to long-lasting effects inherent of stability, and to a reduced level of turbulent mixing. The first part of the wind-tunnel floor must not be cooled if turbulence quantities are to vary smoothly with height. Closely horizontally homogeneous flow is demonstrated, where profiles are comparable or closely comparable with atmospheric data in terms of local similarity and functions of normalized height. The ratio of boundary-layer height to surface Obukhov length, and the surface heat flux, are functions of the bulk Richardson number, independent of horizontal homogeneity. Surface heat flux rises to a maximum and then decreases. Springer Netherlands 2018-02-21 2018 /pmc/articles/PMC6438612/ /pubmed/30996390 http://dx.doi.org/10.1007/s10546-018-0337-7 Text en © The Author(s) 2018 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Research Article
Hancock, Philip E.
Hayden, Paul
Wind-Tunnel Simulation of Weakly and Moderately Stable Atmospheric Boundary Layers
title Wind-Tunnel Simulation of Weakly and Moderately Stable Atmospheric Boundary Layers
title_full Wind-Tunnel Simulation of Weakly and Moderately Stable Atmospheric Boundary Layers
title_fullStr Wind-Tunnel Simulation of Weakly and Moderately Stable Atmospheric Boundary Layers
title_full_unstemmed Wind-Tunnel Simulation of Weakly and Moderately Stable Atmospheric Boundary Layers
title_short Wind-Tunnel Simulation of Weakly and Moderately Stable Atmospheric Boundary Layers
title_sort wind-tunnel simulation of weakly and moderately stable atmospheric boundary layers
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6438612/
https://www.ncbi.nlm.nih.gov/pubmed/30996390
http://dx.doi.org/10.1007/s10546-018-0337-7
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