<abstract xmlns="http://www.w3.org/1999/xhtml"><p> This study examines the problem of flow resistance due to rigid vegetation in open channel flow. The reliability of the conventional flow resistance equations (i.e. Keulegan, Manning and Chézy-Bazin) for vegetated flows at high submergence, i.e. h/k >5, (where h = flow depth and k = vegetation height) is assessed. Several modern flow resistance equations based on a two-layer approach are examined, showing that they transform into the conventional equations at high submergences. To compare the conventional flow resistance equations at high submergences, an experimental methodology is proposed and applied to the experimental data reported in the literature and collected for this study. The results demonstrate the reliability of the Keulegan equation in predicting the flow resistance. Based on the obtained results, a model to evaluate the Nikuradse equivalent sand-grain roughness, kN, starting from the vegetation height and density, is proposed and tested.</p></abstract>

This study examines the problem of flow resistance due to rigid vegetation in open channel flow. The reliability of the conventional flow resistance equations (i.e. Keulegan, Manning and Chézy-Bazin) for vegetated flows at high submergence, i.e. h/k >5, (where h = flow depth and k = vegetation height) is assessed. Several modern flow resistance equations based on a two-layer approach are examined, showing that they transform into the conventional equations at high submergences. To compare the conventional flow resistance equations at high submergences, an experimental methodology is proposed and applied to the experimental data reported in the literature and collected for this study. The results demonstrate the reliability of the Keulegan equation in predicting the flow resistance. Based on the obtained results, a model to evaluate the Nikuradse equivalent sand-grain roughness, kN, starting from the vegetation height and density, is proposed and tested.

Use of conventional flow resistance equations and a model for the Nikuradse roughness in vegetated flows at high submergence

Journal of Hydrology and Hydromechanics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

This study examines the problem of flow resistance due to rigid vegetation in open channel flow. The reliability of the conventional flow resistance equations...

Use of conventional flow resistance equations and a model for the Nikuradse roughness in vegetated flows at high submergence

Published Online: Nov 22, 2017

Page range: 107 - 120

Received: Jul 27, 2016

Accepted: Mar 14, 2017

DOI: https://doi.org/10.1515/johh-2017-0028

Keywords
Open channel flows, Vegetated flows, Rigid vegetation, Flow resistance, Roughness coefficients, Nikuradse equivalent sand-grain roughness

© 2017

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Use of conventional flow resistance equations and a model for the Nikuradse roughness in vegetated flows at high submergence

Published Online: Nov 22, 2017

Page range: 107 - 120

Received: Jul 27, 2016

Accepted: Mar 14, 2017

DOI: https://doi.org/10.1515/johh-2017-0028

KeywordsOpen channel flows, Vegetated flows, Rigid vegetation, Flow resistance, Roughness coefficients, Nikuradse equivalent sand-grain roughness

© 2017

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
Open channel flows, Vegetated flows, Rigid vegetation, Flow resistance, Roughness coefficients, Nikuradse equivalent sand-grain roughness