Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 12 of 12 for “"Bed morphology"”.
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Bed Morphology and Sediment Transport Under Oscillatory Flow
The experiments focused on two aspects of the bed morphology: the study of the ripple planform geometry under a broad range of flow conditions, and the effect of orbital velocities on the ripple size under long water excursions. Regarding the planform geometry of the ripples, the results showed …
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Feedback between erosional morphology, sediment transport and abrasion in the transient adjustment of fluvial bedrock channels
This thesis explores the dependence of bedrock channel incision on coarse sediment supply through laboratory flume experiments and quantitative field observations of evolving channel morphology. Predictions of the saltation-abrasion model (Sklar and Dietrich, 2004) for sediment flux-dependent …
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The fluvial dynamics of confluent meander bends
… flow structure, sediment transport, and bed morphology at river confluences. Previous experimental, field, and modeling studies of confluence dynamics have focused mainly on junctions formed by straight approach channels that meet at angular configurations before entering a straight …
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The fluvial dynamics of compound meander bends
… among spatial patterns of mean flow, turbulence, bed morphology, bank failures and channel migration in compound loops is poorly understood. In particular, field studies of this interaction over the timescale of planform evolution are lacking. The research presented here examines the co-evolution …
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Braided rivers: an exploratory study combining flume experiments and the analysis of remotely-sensed data
… in a 25 x 2.9 m flume of constant slope (1%) and bed material (D50 = 1mm) with sediment supply constrained to match sediment output. As the maximum potential channel width increased, the channel pattern changed from a single channel with alternate bars, to the formation of mid-channel bars, and …
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Hydrodynamics and Morphodynamics in Kinoshita Meandering Channels
… from several disciplines (engineering, geomorphology, ecology, among others), is required for the development of predictive models for river naturalization. Both, basic and applied researches are needed to cover the wide range of spatial- and time-scales found in rivers. Therefore, this …
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Wake characteristics associated with logjams to inform river restoration
… The presence of the logjams alters the bed morphology of the river and availability of habitats. To better understand how design choices for a logjam can impact habitats, important parameters include solid volume fraction (SVF) and channel width. Thus, these two variables were varied in …
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Managing complexity in high-concentration flow modelling aimed at hazard assessment: numerical and practical aspects
… this work embraced the quasi-two phase, mobile-bed approach proposed in Armanini et al. (2009b) and in Rosatti and Begnudelli (2013a), which is implemented in the TRENT2D model. TRENT2D is a quite sophisticated model that solves a system of Partial Differential Equations over a Cartesian mesh by …
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Flow structure of an asymmetric large river confluence
… of three-dimensional velocity components and bed topography at the confluence of the Wabash River and Embarras River along the Illinois-Indiana border reveal a complex hydrodynamic environment that responds dynamically to changes in momentum flux ratio of the incoming flows and to the effects …
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The sedimentology and dynamics of mega-dunes, Jamuna river, Bangladesh
This thesis quantifies the occurrence, morphology and flow dynamics of dune bcdforms in the main rivers of Bangladesh: the Jamuna, Meghna and Ganges. Field work was conducted as part of the River Survey Project (Bangladesh Flood Action Plan 24) between November 1993 and March 1996, hence …
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Towards an understanding of mass transfer and hydrodynamics in packed bed reactors using Nuclear Magnetic Resonance
… phenomena that govern the performance of packed bed reactors. The aim of this work is to gain insight into factors that affect the process of fines deposition and mass transfer inside packed beds to ultimately enable optimisation of these processes. Although mass transfer correlations exist for …
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Flow, sediment transport and bedforms under combined flows
… in natural environments and generates a range of bedforms on sandy beds. Combined-flow bedforms are abundant in coastal and lacustrine environments, as well as in their ancient counterparts in the rock record. However, few experimental studies have focused on the relationship between the …