Flow in Compound Channel with Abrupt Floodplain Contraction
Publication: Journal of Hydraulic Engineering
Volume 132, Issue 9
Abstract
Flooding rivers usually present transition reaches where the floodplain width can significantly vary. The present study focuses on an abrupt floodplain contraction (mean angle 22°) in order to determine whether one-dimensional (1D) models, developed for straight and slightly converging geometry, are equally valid for such a geometry. Experiments on a contraction model were carried out in an asymmetric compound channel flume. Severe mass and momentum transfers from the floodplain towards the main channel were observed, giving rise to a noteworthy transverse slope of the water surface and different head loss gradients in the two subsections. Three 1D models and one 2D simulation were compared to experimental measurements. Each 1D model incorporates a specific approach for the modeling of the momentum exchange at the interface boundary between the main channel and the floodplain. The increase of the lateral mass transfer generates moderate errors on the water level values but significant errors on the discharge distribution. Erroneous results arise because of incorrect estimations of both momentum exchange due to lateral mass transfers and boundary conditions which are imposed by the tested 1D models.
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Acknowledgments
Experiments in CNR flume were funded by PNRH99-04 research programme. D. Bousmar, N. Rivière, and S. Proust travel costs were supported by the Tournesol programme Grant 02947VM funded by EGIDE, France and CGRI, Communauté française de Belgique.
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Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 132 • Issue 9 • September 2006
Pages: 958 - 970
Copyright
© 2006 ASCE.
History
Received: Nov 16, 2004
Accepted: Sep 9, 2005
Published online: Sep 1, 2006
Published in print: Sep 2006
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