<abstract xmlns="http://www.w3.org/1999/xhtml"><p> This study addresses a particular phenomenon in open channel flows for which the basic assumption of hydrostatic pressure distribution is essentially invalid, and expands previous suggestions to flows where streamline curvature is significant. The proposed model incorporates the effects of the vertical curvature of the streamline and steep slope, in making the pressure distribution non-hydrostatic, and overcomes the accuracy problem of the Saint-Venant equations when simulating curvilinear free surface flow problems. Furthermore, the model is demonstrated to be a higher-order one-dimensional model that includes terms accounting for wave-like variations of the free surface on a constant slope channel. Test results of predicted flow surface and pressure profiles for flow in a channel transition from mild to steep slopes, transcritical flow over a short-crested weir and flow with dual free surfaces are compared with experimental data and previous numerical results. A good agreement is attained between the experimental and computed results. The overall simulation results reveal the satisfactory performance of the proposed model in simulating rapidly varied gravity-driven flows with predominant non-hydrostatic pressure distribution effects. This study suggests that a higher-order pressure equation should be used for modelling the pressure distribution of a curvilinear flow in a steeply sloping channel.</p></abstract>

This study addresses a particular phenomenon in open channel flows for which the basic assumption of hydrostatic pressure distribution is essentially invalid, and expands previous suggestions to flows where streamline curvature is significant. The proposed model incorporates the effects of the vertical curvature of the streamline and steep slope, in making the pressure distribution non-hydrostatic, and overcomes the accuracy problem of the Saint-Venant equations when simulating curvilinear free surface flow problems. Furthermore, the model is demonstrated to be a higher-order one-dimensional model that includes terms accounting for wave-like variations of the free surface on a constant slope channel. Test results of predicted flow surface and pressure profiles for flow in a channel transition from mild to steep slopes, transcritical flow over a short-crested weir and flow with dual free surfaces are compared with experimental data and previous numerical results. A good agreement is attained between the experimental and computed results. The overall simulation results reveal the satisfactory performance of the proposed model in simulating rapidly varied gravity-driven flows with predominant non-hydrostatic pressure distribution effects. This study suggests that a higher-order pressure equation should be used for modelling the pressure distribution of a curvilinear flow in a steeply sloping channel.

Modelling free surface flow with curvilinear streamlines by a non-hydrostatic model

David & James – Engineering and Environmental Consultancy, 204 Albion Road, Victoria 3350, Australia

Journal of Hydrology and Hydromechanics

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

This study addresses a particular phenomenon in open channel flows for which the basic assumption of hydrostatic pressure distribution is essentially invalid,...

Modelling free surface flow with curvilinear streamlines by a non-hydrostatic model

Published Online: Jul 08, 2016

Page range: 281 - 288

Received: Oct 08, 2015

Accepted: Apr 15, 2016

DOI: https://doi.org/10.1515/johh-2016-0028

Keywords
Curvilinear flow, Finite difference method, Hydraulic structures, Hydrodynamics, Non-hydrostatic pressure, Nonuniform flow

© 2016

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

Modelling free surface flow with curvilinear streamlines by a non-hydrostatic model

Published Online: Jul 08, 2016

Page range: 281 - 288

Received: Oct 08, 2015

Accepted: Apr 15, 2016

DOI: https://doi.org/10.1515/johh-2016-0028

KeywordsCurvilinear flow, Finite difference method, Hydraulic structures, Hydrodynamics, Non-hydrostatic pressure, Nonuniform flow

© 2016

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

Keywords
Curvilinear flow, Finite difference method, Hydraulic structures, Hydrodynamics, Non-hydrostatic pressure, Nonuniform flow