Print Email Facebook Twitter Flow and bathymetry in sharp open-channel bends: Experiments and predictions Title Flow and bathymetry in sharp open-channel bends: Experiments and predictions Author Zeng, J. Constantinescu, G. Blanckaert, K. Weber, L. Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Date 2008-09-03 Abstract This paper focuses on experiments and simulations conducted in very sharp open-channel bends with flat and equilibrium bathymetry, corresponding to the initial and final phases of the erosion and deposition processes, respectively. The study of flow in curved open bends is relevant for flow in natural river configurations, as most river reaches are not straight. The configuration considered in the present work was designed as a test case in which the role of the cross-sectional flow is more severe than in meandering natural river reaches (radius of curvature of the channel is close to the channel width) and, thus, can serve for validation of numerical models used to predict flow and sediment transport in river engineering applications. This paper presents detailed new experimental data on the equilibrium bathymetry as well as depth-averaged distributions, vertical profiles, and cross-sectional patterns of the streamwise velocity, the cross-stream circulation, streamwise vorticity, and the turbulent kinetic energy at the initial and final stages of the erosion and deposition processes. The numerical simulations are performed using a three-dimensional nonhydrostatic RANS model for flow, sediment transport, and bathymetry, which employs fine meshes, accounts for the effect of small bed forms, and avoids the use of the law of the wall. The model predicts, rather accurately, the distribution of the streamwise velocity, the cross-stream circulation, and the turbulent kinetic energy in the simulations conducted with a fixed (flat and deformed bed corresponding to equilibrium conditions) prescribed bathymetry. In the case of a simulation conducted with loose bed, the model predicts satisfactorily the main features of the bathymetry at equilibrium conditions, despite the fact that including the interaction between the flow and the bathymetry increases the overall uncertainty in the model predictions. Results indicate that both improvements in the level of turbulence modeling and in the modeling of the sediment transport would allow further improvement in the predictive capabilities of morphodynamic models. Subject open-channel flownumerical modelturbulence modelingcurvaturechannel bendexperimentsmovable bedsecondary flow To reference this document use: http://resolver.tudelft.nl/uuid:87c974f7-a6b1-4575-8767-fdac5c5a7081 DOI https://doi.org/10.1029/2007WR006303 Publisher American Geophysical Union ISSN 0043-1397 Source http://europa.agu.org/?view=article&uri=/journals/wr/wr0809/2007WR006303/2007WR006303.xml Source Water Resources Research, 44, 2008 Part of collection Institutional Repository Document type journal article Rights (c) 2008 The Author(s); American Geophysical Union Files PDF Blanckaert_2008.pdf 1.52 MB Close viewer /islandora/object/uuid:87c974f7-a6b1-4575-8767-fdac5c5a7081/datastream/OBJ/view