000202624 001__ 202624
000202624 005__ 20180913062757.0
000202624 037__ $$aARTICLE
000202624 245__ $$aSediment transport in mountain rivers
000202624 269__ $$a2014
000202624 260__ $$c2014
000202624 336__ $$aJournal Articles
000202624 520__ $$aThe paper reviews our recent attempts at modelling bed load transport in mountain rivers. This is a longstanding issue that has attracted considerable attention over the last century. While a number of field and laboratory studies have been instrumental in getting the big picture, there is a clear lack of efficient methods for predicting bed evolution and particle flux. Most approaches to bed load transport have emphasized the existence of a oneto-one relationship between the particle flux and water discharge, but this result conflicts with the spread of data, which often spans over several orders of magnitude. A possible interpretation lies in the significance of the fluctuations of the particle flux together with the propagation of bed forms. We have therefore developed a theoretical model based on birth-death Markov processes to describe the random exchanges between the stream and bed, which then allows us to derive a governing equation for the particle flux fluctuations. We end up with the probability distribution function of the sediment transport rate. A striking feature is the existence of large fluctuations even under steady flow conditions. Numerical simulations have been carried out to compute the flow features, for the moment with no sediment transport. These simulations have shown that the kinematic wave approximation (which leads to a significant simplification of the Saint-Venant equation into a nonlinear advection equation) performs well for a wide range of water discharges. Remarkably, it has been found that under steady flow conditions, the local flow variables (wetted section and water discharge, or flow depth and mean velocity) exhibit a Froude similarity, i.e. regardless of the water discharge, the Froude number remains fairly constant at a given place of the river. Future work will consider the inclusion of a stochastic sediment transport equation in the Saint-Venant equations.
000202624 6531_ $$aSediment transport
000202624 6531_ $$aMountain river
000202624 700__ $$0240366$$aAncey, Christophe$$g148669
000202624 700__ $$aBohorquez, Patricio
000202624 700__ $$aBardou, Eric
000202624 773__ $$j100$$kSeptember$$tErcoftac Bulletin
000202624 8564_ $$s8824469$$uhttps://infoscience.epfl.ch/record/202624/files/ancey_bohorquez_bardou%20ercoftac%202014.pdf$$yn/a$$zn/a
000202624 909C0 $$0252029$$pLHE$$xU10257
000202624 909CO $$ooai:infoscience.tind.io:202624$$particle$$pENAC
000202624 917Z8 $$x106556
000202624 917Z8 $$x106556
000202624 917Z8 $$x106556
000202624 937__ $$aEPFL-ARTICLE-202624
000202624 973__ $$aEPFL$$rNON-REVIEWED$$sPUBLISHED
000202624 980__ $$aARTICLE