Experimental and numerical findings on the long-term evolution of migrating alternate bars in alluvial channels

Migrating alternate bars form in alluvial channels as a result of morphodynamic instability. Extensive literature can be found on their origin and short-term development, but their long-term evolution has been poorly studied so far. In particular, it is not clear whether migrating bars eventually reach a (dynamic) equilibrium, as in previous...

Experimental and numerical evidence for intrinsic nonmigrating bars in alluvial channels

Experimental observations on long-term behavior of migrating alternate bars

Migrating alternate bars form in alluvial channels as a result of morphodynamic instability. Extensive literature can be found on their origin and short-term development, but their long-term evolution has been poorly studied so far. In particular, it is not clear whether they eventually reach an equilibrium shape, since short-term experiments...

Experimental and numerical evidence for intrinsic nonmigrating bars in alluvial channels

Alternate bars in straight alluvial channels are migrating or nonmigrating. The currently accepted view is that they are nonmigrating if the width-to-depth ratio is at the value of resonance or if the bars are forced by a persistent local perturbation. We carried out 2-D numerical computations and a long-duration mobile-bed flume experiment to...

Long-duration laboratory experiment of slow development of steady alternate bars

The current view is that migrating bars are the result of morphodynamic instability in straight or mildly-sinuous alluvial channels and are therefore an inevitable feature of alluvial river beds. Steady bars, instead, require some external forcing or specific morphodynamic conditions to develop. Yet, recent numerical tests showed that steady...