LA PERTE DE CHARGE DANS LES CANAUX A FOND MOBILE EXAMEN DE L’EFFET DES FORMES DU FOND

Abstract

The open channel flow is often calculated by a typical formula (as Strickler formula) that ignores the friction due to the bedforms, since the works of Einstein and Barbarossa (1952), several formulas and approaches have been proposed to express this friction. In this article we used 2790 flume data to show the effect of the bedforms on flow resistance, in this way, we compare the flow depths calculated by the formulas of Strickler and Karim (1995) (taking into account bedfroms) to the measured flow depths. In the flat beds, the results obtained by Strickler formula are the best, it explains 71% of data with errors less than 20%, for Karim (1995) formula this percentage is just 65%. For bed with bedforms, it is rather the contrary; the formula of Karim (1995) explained 74% of the data with error less than 20%, against Strickler's formula which explains only 56% of the same data. In fact, in the absence of a universal flow resistance formula, the bedforms friction consideration is unavoidable