Stability Diagram of upper flow regime bedforms. An experimental study

Abstract

Water flowing over a bed made of silici-clastic material forms bedforms. A stability diagram for these bedforms is available for the lower flow regime where the Froude number < 0.8. No such diagram is available for the upper flow regime (Fr > 0.8). Experiments in a tiltable flume show that the bedforms for the upper flow regime can be characterized as: upper plane bed, antidunes, chute and pools and cyclic steps. These bedforms are plotted in a stability showing the relation between the dimensionless grain size and the ratio of minimum and maximum Froude number (before and after the hydraulic jump if present) showing proof of concept for such a stability diagram.