Discussion of "Transition between Two Bed-Load Transport Regimes: Saltation and Sheet-Flow" by P. Gao
Discussion de "transition entre deux régimes de transport par charriage : la saltation et le sheet flow" de P. Gao
Résumé
The author presented an interesting theoretical model for predicting the onset of the sheet-flow regime. It introduces the parameter Pb, which characterizes the proportion of grains moved from the surface layer. The proposed relationship for Pb is however derived from the bed-load formula by Abrahams and Gao (2006), which yields a nearly constant Shields parameter equal 0.5, a curious result that merits discussion.