LINEAR APPROXIMATION OF OPEN-CHANNEL FLOW ROUTING WITH BACKWATER EFFECT

Simon Munier (1) , Xavier Litrico (1) , Gilles Belaud (1)

1 UMR G-EAU - Gestion de l'Eau, Acteurs, Usages

This paper proposes a new model for linear flow routing in open-channels. The proposed model, called LBLR for Linear Backwater Lag and Route, is a first order with delay model that explicitly takes into account two parameters which are usually neglected: 1) the downstream boundary condition and 2) the nonuniform flow conditions, both of which are shown to have a strong influence on the flow dynamics. The model parameters are obtained analytically from the pool characteristics (geometry, friction, discharge and downstream boundary condition). A frequency domain approach is used to compute the frequency response of the linearized Saint-Venant equations. This model is then approximated by a first order plus delay model using the moment matching method. The proposed model is shown to perform better than existing models when the flow is affected by backwater and/or by different downstream boundary conditions from the one corresponding to uniform flow.

Mots clés: Open-channel flow; Laplace transform; frequency response; Saint-Venant equations; time-delay; flow routing

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]; Dynamique des Fluides [physics.flu-dyn]

Simon Munier, Xavier Litrico, Gilles Belaud. LINEAR APPROXIMATION OF OPEN-CHANNEL FLOW ROUTING WITH BACKWATER EFFECT. 32nd Congress of the International Association of Hydraulic Engineering and Research, 2007, Venice, Italy. 10p. ⟨hal-00682695⟩