Risk of Sediment Erosion and Suspension in Turbulent Flows

It is shown how some basic probability tools may help in the characterization of the turbulent processes involved in the mechanics of sediment transport. Both the initiation of sediment motion and the threshold for sediment suspension are analyzed in a stochastic frame of work. Isorisk curves are constructed based upon some minimum experimental information. The well-known Shieldsʹ curve is shown to correspond to an erosion risk of approximately 40%. These concepts are believed to be of importance for the design of movable-bed channels as well as for future experimental investigations, which are indeed necessary for computing the risk for higher values of the particle Reynolds number. Finally, an approximate methodology is proposed for computing the risk of erosion.