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Showing 1 to 13 of 13 for “"mobile-bed"”.
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The effect of dikes on water surfaces in a mobile bed
… levels, this study considers effect of movable bed, which has been largely neglected in previous studies. Previous research on this topic has relied on field data, numerical modeling and physical modeling. A majority of the modeling has been a fixed bed condition and has not accounted for the …
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Experimental Study of Pathogenic Microorganism Resuspension from Mobile Bed Sediment in Irrigational Canals
… particles. The resuspension of pathogens from bed sediment in irrigation canals impairs the quality of overlaying water and can result in the contamination of fresh produces. Sediments are known to be potential reservoirs of pathogenic microorganisms. Pathogens’ concentration in the water is …
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JEMEZ RIVER CASE STUDY: UTILIZING A FROUDE NUMBER SIMILITUDE PHYSICAL MODEL, 1-D MOBILE BED NUMERICAL MODEL, AND A 2-D FIXED BED NUMERICAL MODEL FOR WEIR DESIGN INSIGHT
… healthy upstream riparian vegetation. Localized bed scour began to occur just downstream of the Jemez Weir following construction. The United States Army Corps of Engineers (USACE) built the structure in 2003 and developed a HEC-RAS model in 2010 to re-evaluate the long term bed degradation …
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Two-phase modelling of debris flow over composite topography: theoretical and numerical aspects
… Complex topography is related to complicated bed elevation variety inasmuch as there are slopes, channels, human artifacts and so on. On the other hand, topography is composite because every type of flow can encounter two different bed behaviors: the mobile bed and the fixed bed. In the first …
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Numerical Modeling of River Diversions in the Lower Mississippi River
… and the distributaries. A 3-D unsteady flow mobile-bed model (ECOMSED; HydroQual 2002) of the Lower MR reach between Belle Chasse (RM 76) and downstream of Main Pass (RM 3) was calibrated using field sediment data from 2008 – 2010 (Nittrouer et al. 2008; Allison, 2010). The model was used to …
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Numerical Simulation of Unsteady Hydrodynamics in the Lower Mississippi River
… rise. This study utilized HEC-RAS 4.0, a 1-D mobile-bed numerical model, which was calibrated using a discharge hydrograph at Tarbert Landing and a stage hydrograph at the Gulf of Mexico, to calculate the hydrodynamics of the river. The model showed that RSLR will decrease the capacity of the …
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Hydrodynamics and sedimentary structures of antidunes in gravel and sand mixtures
… the current literature available on antidune bedforms and their hydrodynamic environment, alongside recent studies of the turbulence environments associated with bedforms in unidirectional flow. Based on this understanding, three suites of experiments were designed and conducted to elucidate …
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A Generalized Log-Law Formulation For a Wide Range of Boundary Roughness Conditions Encountered in Streams
… and large-scale roughness elements comprised of mobile bedforms. The method resulted in similar values of normalized zero-plane displacement for all roughness types considered. The ratios of zero-plane displacement, dh, to roughness height, ks, were 0.20 and 0.26 for the sediment- and …
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Determination of Optimal Stable Channel Profiles
… an optimal stable channel; a channel with a flat-bed region over which bedload transport occurs, and curving bank regions composed of particles that are all in a state of incipient motion. It is the combination of this channel geometry and the phenomenon of momentum-diffusion, that allows the …
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Numerical simulation of an optimal channel cross-section
… coefficient of static friction of the channel bed material, (2) lift-to drag ratio, (3) grain size of the bed material, (4) water discharge, and (5) longitudinal slope of the channel. The term optimal stable channel refers to a channel capable of transporting sediment along a flat bed but whose …
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Effects of rigid stems on sediment transport
… other hand, the presence of vegetation in riverbed modifies flow structure, flow resistance, sediment transport and morphology. Each single modification has been largely studied, but the knowledge on the mutual relationships are still limited. This project faces a part of these still-unknown …
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Turbulent interactions between stream flow and near-subsurface flow: a laboratory approach using particle image velocimetry and refractive index matching
Turbulent flow over a rough, porous gravel bed (particle diameter, D = 1.27 cm) is investigated in the laboratory using particle image velocimetry (PIV) and refractive index matching (RIM). This combination allows for detailed examination of flow fields both in the near-bed region and within the …
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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 …