Variation of the critical Shields number with slope

It is very common to consider a constant critical Shields number for rough turbulent flows. Yet, all available studies and data indicate a slope dependence of this parameter. This study presents a new definition for the incipient motion condition. New results confirm a slope dependence. This result has strong consequences on bed load prediction as when flows occur close to the incipient motion conditions, slight changes in the Shields stress value produce changes