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Article: Velocity and concentration measurements in initial region of submerged round jets in stagnant environment and in coflow

TitleVelocity and concentration measurements in initial region of submerged round jets in stagnant environment and in coflow
Authors
KeywordsDilution
Flow characteristics
Jets
Reynolds number
Issue Date2009
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/wps/find/journaldescription.cws_home/711617/description#description
Citation
Journal Of Hydro-Environment Research, 2009, v. 3 n. 1, p. 21-34 How to Cite?
AbstractVelocity and concentration fields are measured in submerged round jets in a stagnant environment and in coflow using laser Doppler anemometry and laser-induced fluorescence. Measurements are made in the initial region within distances of 40 jet exit diameter at jet Reynolds number between 1000 and 5000 and coflow-to-jet velocity ratio from 0 to 0.43. Different behaviors of jet spreading and dilution are found in jets at three different ranges of Reynolds number in which the jets are classified as initially laminar, transitional or turbulent. In the zone of established flow, the jet centerline velocity and concentration decay with downstream distance at different rates in the three groups of jets. For jets in coflow, axial development of normalized forms of centerline mean excess velocity and mean concentration at different velocity ratios can be reasonably well collapsed onto universal trends through the use of momentum length scale. Turbulence properties inside a jet are increased by the presence of a strong coflow. Inside the zone of flow establishment, some strange features are observed on jet turbulence properties. The length of zone of flow establishment increases from the turbulent jets, to the transition jets and to the laminar jets. The zone lengths for concentration are shorter than those for velocity by one to two jet exit diameters. Both lengths are shortened further in the presence of a coflow. For jets a stagnant environment and in the strong jet flow region of jets in coflow, jet widths increase linearly with downstream distance in transitional and turbulent jets. Self-similarity of radial profiles of mean velocity or excess velocity, mean concentration, turbulence intensities and concentration fluctuation level is explored in the zone of established flow. © 2009 International Association for Hydraulic Engineering and Research, Asia Pacific Division.
Persistent Identifierhttp://hdl.handle.net/10722/137242
ISSN
2015 Impact Factor: 1.971
2015 SCImago Journal Rankings: 0.641
ISI Accession Number ID
Funding AgencyGrant Number
Research Grants Council of Hong KongHKU 7517/03E
Funding Information:

The investigation is supported by a research grant (HKU 7517/03E) awarded by the Research Grants Council of Hong Kong. The authors wish to thank Mr. P. Liu for his assistance in carrying out some LDA measurements.

References
Grants

 

DC FieldValueLanguage
dc.contributor.authorXia, LPen_HK
dc.contributor.authorLam, KMen_HK
dc.date.accessioned2011-08-26T14:21:40Z-
dc.date.available2011-08-26T14:21:40Z-
dc.date.issued2009en_HK
dc.identifier.citationJournal Of Hydro-Environment Research, 2009, v. 3 n. 1, p. 21-34en_HK
dc.identifier.issn1570-6443en_HK
dc.identifier.urihttp://hdl.handle.net/10722/137242-
dc.description.abstractVelocity and concentration fields are measured in submerged round jets in a stagnant environment and in coflow using laser Doppler anemometry and laser-induced fluorescence. Measurements are made in the initial region within distances of 40 jet exit diameter at jet Reynolds number between 1000 and 5000 and coflow-to-jet velocity ratio from 0 to 0.43. Different behaviors of jet spreading and dilution are found in jets at three different ranges of Reynolds number in which the jets are classified as initially laminar, transitional or turbulent. In the zone of established flow, the jet centerline velocity and concentration decay with downstream distance at different rates in the three groups of jets. For jets in coflow, axial development of normalized forms of centerline mean excess velocity and mean concentration at different velocity ratios can be reasonably well collapsed onto universal trends through the use of momentum length scale. Turbulence properties inside a jet are increased by the presence of a strong coflow. Inside the zone of flow establishment, some strange features are observed on jet turbulence properties. The length of zone of flow establishment increases from the turbulent jets, to the transition jets and to the laminar jets. The zone lengths for concentration are shorter than those for velocity by one to two jet exit diameters. Both lengths are shortened further in the presence of a coflow. For jets a stagnant environment and in the strong jet flow region of jets in coflow, jet widths increase linearly with downstream distance in transitional and turbulent jets. Self-similarity of radial profiles of mean velocity or excess velocity, mean concentration, turbulence intensities and concentration fluctuation level is explored in the zone of established flow. © 2009 International Association for Hydraulic Engineering and Research, Asia Pacific Division.en_HK
dc.languageengen_US
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/wps/find/journaldescription.cws_home/711617/description#descriptionen_HK
dc.relation.ispartofJournal of Hydro-Environment Researchen_HK
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.rightsNOTICE: this is the author’s version of a work that was accepted for publication in Journal of Hydro-Environment Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Hydro-Environment Research, 2009, v. 3 n. 1, p. 21-34. DOI: http://dx.doi.org/10.1016/j.jher.2009.03.002-
dc.subjectDilutionen_HK
dc.subjectFlow characteristicsen_HK
dc.subjectJetsen_HK
dc.subjectReynolds numberen_HK
dc.titleVelocity and concentration measurements in initial region of submerged round jets in stagnant environment and in coflowen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1570-6443&volume=3&issue=1&spage=21&epage=34&date=2009&atitle=Velocity+and+concentration+measurements+in+initial+region+of+submerged+round+jets+in+stagnant+environment+and+in+coflow-
dc.identifier.emailLam, KM:kmlam@hku.hken_HK
dc.identifier.authorityLam, KM=rp00134en_HK
dc.description.naturepostprint-
dc.identifier.doi10.1016/j.jher.2009.03.002en_HK
dc.identifier.scopuseid_2-s2.0-67349164340en_HK
dc.identifier.hkuros190695en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-67349164340&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume3en_HK
dc.identifier.issue1en_HK
dc.identifier.spage21en_HK
dc.identifier.epage34en_HK
dc.identifier.isiWOS:000281648100004-
dc.publisher.placeNetherlandsen_HK
dc.relation.projectExperimental investigation on the zone of flow establishment in a submerged round jet in a current-
dc.identifier.scopusauthoridXia, LP=7201955947en_HK
dc.identifier.scopusauthoridLam, KM=7403656958en_HK

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