Abstract
This paper presents results detailing the quantitative visualization of flow fields associated with natural sand dunes, Fraser River Estuary, Canada, using the complementary approaches of laboratory modelling and field instrumentation. Ultrasonic Doppler velocity profiling is used in the laboratory to elucidate the mean flow fields of low-angle dunes (leeside slope angle ≈14°) that are typical of many large natural rivers. These dunes do not possess a zone of permanent flow separation in the dune leeside and have a velocity structure that is dominated by the effects of flow acceleration and deceleration generated by topographic forcing of flow over the dune form. Turbulence associated with these dunes appears linked to both longer-period shear layer flap** and eddy generation along the shear layer. The field study uses acoustic Doppler profiling to reveal similar mean flow patterns and shows that flow is dominated by deceleration in the leeside without the presence of a region of permanent separated flow.
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Jim Best: He gained a B.Sc. degree in Geology and Geography in 1979 from the University of Leeds and then obtained his Ph.D., concerning the flow and sediment dynamics of open channel confluences, at Birkbeck College, University of London, in 1985. After a lectureship in Geology at the University of Hull from 1983-1988, he was appointed as a Lecturer in Earth Sciences at the University of Leeds in 1988. He gained a readership in Experimental Sedimentology in 1998 and was appointed to a personal chair in Process Sedimentology in 2000. His research interests centre around the investigation of mean flow, turbulence and sediment dynamics in natural environments from both a laboratory and field-based perspective, including river and density current dynamics, investigation of the influence of sediment transport on turbulence and application of these topics in both modern and ancient sedimentary environments.
Ray Kostaschuk: He obtained his B.Sc. in Geography from Simon Fraser University in 1976 and followed this with a Masters degree from the University of Calgary in 1980. His doctoral research, conducted at McMaster University on sedimentation in a fjord-head delta, Bella Coola, British Columbia, was completed in 1983 and was followed by a three-year postdoctoral fellowship at the University of British Columbia. Appointment to an Assistant Professorship at the Department of Geography, University of Guelph, in 1985 was followed by promotion to both associate and full professorship in 1989 and 1995. His research interests include study of the hydraulics and sediment transport in rivers and estuaries, sediment accumulation rates in estuaries, the geomorphic effects of tropical cyclones and the field-based quantification of flow and sediment transport using acoustic methods.
Paul Villard: He gained his B.Sc. and M.Sc. in Geography from the University of Guelph in 1993 and 1996, and followed this by study of the influence of wave groups on sand resuspension over bedforms to gain his Ph.D. from the University of Auckland, New Zealand, in 1999. Since 1999 he has held a NSERC postdoctoral fellowship at the University of British Columbia. His research interests include the fluid dynamics and sediment transport of bedforms in both unidirectional and oscillatory flows, field and laboratory based quantification of turbulence and fluid dynamics and the influence of snow avalanches on sediment erosion in mountain terrain.
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Best, J.L., Kostaschuk, R.A. & Villard, P.V. Quantitative visualization of flow fields associated with alluvial sand dunes: Results from the laboratory and field using ultrasonic and acoustic doppler anemometry. J Vis 4, 373–381 (2001). https://doi.org/10.1007/BF03183900
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DOI: https://doi.org/10.1007/BF03183900