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Stratified shear flows over a simulated three-dimensional urban heat island

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dc.contributor.authorSethuRaman, S., author
dc.contributor.authorCermak, J. E. (Jack E.), author
dc.contributor.authorFluid Dynamics and Diffusion Laboratory, College of Engineering, Colorado State University, publisher
dc.date.accessioned2017-11-27T15:16:29Z
dc.date.available2017-11-27T15:16:29Z
dc.date.issued1973-08
dc.descriptionCER73-74SS-JEC4.
dc.descriptionAugust 1973.
dc.descriptionIncludes bibliographical references.
dc.descriptionPrepared under Office of Naval Research, project no. NR 062-414/6-6-68 (Code 438).
dc.description.abstractThree-dimensional airflow over a rectangular heat island was studied for various conditions of approach flow in a wind tunnel. Three different thermal stratifications of the approach flow were selected for the study -- neutral, ground based and elevated inversions. For each of these flows studies were conducted with and without roughness over the heat island for the conditions with and without heating of the island. Approach flow temperature profiles were modeled according to atmospheric data available in the literature. For each of the twelve cases mentioned above, measurements of mean wind velocity, longitudinal velocity fluctuations, mean temperature and temperature fluctuations were made. In addition, mean concentration measurements of a radioactive gas released from a two-dimensional, ground-level line source upwind of the heat island were also made. Flow patterns were visualized for different cases with the help of a passive smoke source. Comparisons of data from the wind-tunnel measurements with the field data were made. Three-dimensional measurements of the mean wind velocity, temperature and turbulence have yielded valuable information concerning the flow of air around a typical urban heat island. The mechanisms of the heat island observed in the wind tunnel for different stratified flows were very similar to those observed in the field. The urban heat island plume that passes aloft downwind causes an appreciable reverse flow onto the heat island. The helical vortices at the edge of the heat island cause a reduction in the turbulence level resulting in high concentrations of the mass released from a continuous line source upwind of the heat island. A theoretical model based on linearized equations of motions incorporating a boundary layer type velocity profile has been developed to predict the urban excess temperatures and velocities. Theoretical results compare fairly well with data obtained in the laboratory and in the field.
dc.description.sponsorshipUnder Contract no. N00014-68-A-0493-0001.
dc.format.mediumreports
dc.identifier.urihttps://hdl.handle.net/10217/185075
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relationCatalog record number (MMS ID): 991012240159703361
dc.relationTA7.C6 CER 73/74-4
dc.relation.ispartofCivil Engineering Reports
dc.relation.ispartofProject THEMIS technical report, no. 22
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subject.lcshAtmospheric circulation
dc.subject.lcshDiffusion
dc.subject.lcshAir -- Pollution
dc.subject.lcshUrban climatology
dc.titleStratified shear flows over a simulated three-dimensional urban heat island
dc.typeText
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