Title: Friction coefficient equation in a gravel bed under bedload regime using the dimensional analysis

Abstract

The wadis in Algeria organize the beds as gravel by transporting fine sediments form through hydrosedimentary dynamic of intermittent flood events along the time. In this paper, a new flow resistance equation is proposed for gravel bed bedload regime. Due to the field measurements lack in wadis, the study is based on 2147 flume data with friction factor measurements. The development of convenient equation is achieved through theoretical analysis by taking into account wadi dominant parameters based on dimensional analysis. Hence, deduced relationships are considered between friction coefficient f, the flow characteristics, bed grains size, geometric parameter and bed slope. The proposed equation gives satisfactory results; the estimated mean normalized error is less than 17%.