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Title: Open-channel flow through simulated vegetation : turbulence modeling and sediment transport
Authors: López, Fabián, 1962-
Garcia, Marcelo
Keywords: Flow profiles
Numerical modeling
Numerical models
Mathematical modeling
Mathematical models
Open-channel flow
Sediment transport
Vegetation effects
Aquatic vegetation
Publisher: U.S. Army Engineer Waterways Experiment Station
Series/Report no.: Technical Report (Wetlands Research Program (U.S.)) ; no. Technical Report WRP-CP-10
Abstract: The two-equation turbulence model based on the k-ε closure scheme was developed to simulate the flow and turbulence characteristics of open-channel flows through nonemergent vegetation. Once the performance of the model was verified, the flow structure of vegetated open channels was numerically simulated. Simulated rigid and flexible plants were used to validate the model. Finally, dimensional analysis allowed identification of the dimensionless parameters that govern suspended sediment transport processes in the presence of vegetation, and thus helped in the design of numerical experiments to investigate the role of different flow properties, sediment characteristics, and vegetation parameters upon the transport capacity. The two-equation turbulence model was found to accurately represent the mean flow and turbulence structure of open channels through simulated vegetation, thus providing the necessary information to estimate suspended sediment transport processes. A reduction of the averaged streamwise momentum transfer toward the bed (i.e., shear stress) induced by the vegetation was identified as the main reason for lower suspended sediment transport capacities in vegetated waterways compared with those observed in nonvegetated channels under similar flow conditions. Simulated proflles of kinematic eddy viscosity were used to solve the sediment diffusion equation, yielding distributions of relative sediment concentration slightly in excess of the ones predicted by the Rousean formula. A power law was found to provide a very good collapse of all the numerically generated data for suspended sediment transport rates in vegetated channels.
Description: Technical Report
Gov't Doc #: Technical Report WRP-CP-10
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Technical Report

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