Please use this identifier to cite or link to this item: http://hdl.handle.net/11422/8840
Type: Artigo
Title: Experimental Investigation of Turbulent Boundary Layers over Steep Two-dimensional Elevations
Author(s)/Inventor(s): Loureiro, Juliana Braga Rodrigues
Freire, Atila Pantaleão Silva
Abstract: Indisponível.
Abstract: This work presents a laboratory study on the behavior of turbulent boundary layers over steep topographic elevations. Two main topics of interest are addressed here: (i) to investigate and characterize the separated flow region that is formed on the leeside of a steep elevation, and (ii) to evaluate the effects of flow stability conditions on the properties of boundary layers also subject to surface changes in elevation. To carry out this task, water channel and wind-tunnel investigations were conducted. For the former research topic, a neutrally stratified boundary layer was simulated in the water-channel of the Hydraulics Laboratory of FEUP. Mean and turbulent velocities were measured through laser-Doppler anemometry. Results provided a thorough description of the inner layers along the hill and inside the recirculation region. The refined near-wall data has contributed to the calculation of the friction velocity along the hill through different methods. For the latter topic, neutral, stable and unstable boundary layers were simulated in a wind-tunnel in the Laboratory of Turbulence Mechanics of COPPE/UFRJ. Simultaneous velocity and temperature fields were measured with the aid of thermal anemometry. These results allowed the characterization of the effects of the stratification on the speed-up factor, i.e. the maximum acceleration of the flow on hilltop. The present paper has introduced the concept of the heat up/down factor, in order to study the behaviour of the temperature field on the crest of the elevation.
Keywords: Flow over hills
Turbulence
Separation
Stratification
Hot-wire anemometry
Laser-Doppler anemometry
Subject CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA::AREAS CLASSICAS DE FENOMENOLOGIA E SUAS APLICACOES::DINAMICA DOS FLUIDOS
Production unit: Núcleo Interdisciplinar de Dinâmica dos Fluidos
Publisher: Springer Verlag
In: Journal of the Brazilian Society of Mechanical Sciences and Engineering
Volume: 27
Issue: 4
Issue Date: 24-Aug-2005
DOI: 10.1590/S1678-58782005000400001
Publisher country: Brasil
Language: eng
Right access: Acesso Aberto
ISSN: 1678-5878
Appears in Collections:Engenharias

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