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Hydraulic Behaviour of Surface Flow in and over Macro-Roughness

Author(s): Jerome Dubois; Anton Schleiss

Linked Author(s): Anton J. Schleiss

Keywords: Hydrology; Hydraulic behaviour; Overland flow; Head loss; Friction function; Macro-roughness; Sheet flow; Laminar flow; Laboratory experiments; Flood generation

Abstract: At present, the possibilities of numerical simulation allow a deterministic approach to physical phenomena. Hydrology takes full advantage of this and develops models based on hydraulic equations to compute the flood generation on a watershed. The solution of these equations of movement requires the knowledge of a coefficient of head loss. Besides hydrological parameters, this coefficient is often the only unknown physical parameter of the model for its adjustment and the quality of its estimation directly influences the quality of the model. Laboratory experiments were conducted on inclined surface covered by glass spheres (marbles) in order to obtain the relation between the velocity and the variable parameters, that is the diameter of marbles, the slope of the surface and the intensity of the rain. These experiments lead to a new relation to compute head loss for a thin flow over macro-roughness. This friction function is valid for laminar flow as well as for turbulent flow.


Year: 1999

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