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dc.contributor.authorAhadi, Mohammad Saeiden
dc.date.accessioned2021-03-23T15:10:53Z
dc.date.available2021-03-23T15:10:53Z
dc.identifier.urihttp://hdl.handle.net/1974/28731
dc.description.abstractBars and pool-riffle sequences are common occurrences in gravel streams, and a major driving force affecting the exchange of groundwater and free surface water in upper river reaches. Such topographic features induce downwelling and upwelling hyporheic flows, essential to the preservation of the river ecosystem. The primary goal of this work is to address the lack of data on hyporheic flows induced by bars and their effect on the streamflow. An extensive laboratory study detailing both the hyporheic and free surface flows is presented. The work is limited to the study of a two-dimensional axisymmetric bar, 1.6 m long and 0.06 m high, over a substrate of finite thickness and subjected to a 0.18 m streamflow depth. It is found that over the upstream side of the bar, the hyporheic flow abstracts a significant amount (10.1%) of water from the free surface flow. Through the combined effect of suction and injection, a pronounced shear layer forms 0.01 - 0.015 m away from the bed surface, leading to intense turbulence activity on the downstream side of the bar. In particular, the region around the location where the hyporheic flow divide line meets the bed surface appears as a preferential region for the generation of eddies, that ultimately grow considerably as they are conveyed downstream, before dissipating. This study is also used as an opportunity to investigate means of acquiring more accurate measurements of streamflow instantaneous velocities using the Nortek Vectrino Profiler. For this purpose, two additional experimental studies are presented. These deal with the minimization or elimination of the saw-tooth pattern in vertical profiles of pertinent quantities (velocities and turbulence stresses), and ways to minimize the instrument's interference region near the bed.en
dc.language.isoengen
dc.relation.ispartofseriesCanadian thesesen
dc.rightsQueen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canadaen
dc.rightsProQuest PhD and Master's Theses International Dissemination Agreementen
dc.rightsIntellectual Property Guidelines at Queen's Universityen
dc.rightsCopying and Preserving Your Thesisen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectHyporheic flowen
dc.subjectGravel baren
dc.subjectNortek Vectrino Profileren
dc.subjectSaw-tooth patternen
dc.subjectInterference regionen
dc.subjectGravel streamen
dc.subjectSeepage ratioen
dc.subjectSuction and injectionen
dc.titleLaboratory Characterization of Turbulent Hyporheic and Free Surface Flows Associated with Bars in Gravel Streams and Related Efforts to Improve Measurement Techniquesen
dc.typethesisen
dc.description.degreePhDen
dc.contributor.supervisorda Silva, Ana Maria Ferreira
dc.contributor.departmentCivil Engineeringen
dc.degree.grantorQueen's University at Kingstonen


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