Our aim in this paper is to illustrate the importance of free water surface effects and sediment transport mode in the morphological evolution of sand dunes to upper stage plane beds. We have analyzed a large number of bed form data, 414 experiments from flumes and field, showing significantly different evolution of dune height and length in shallow (high Froude numbers) and in deep flows (low Froude numbers). In shallow flows, dune heights are observed to grow only in bed load dominant transport regime and start to decay for Suspension numbers greater than 1. Dunes in this case are not observed for Suspension number greater than 2.5. For low Froude numbers, dune heights continue to grow from bed load to suspended load dominant transport regime. Dunes in this case are not observed for Suspension number greater than 5. Furthermore, dunes in shallow flows reach significantly greater heights compared to dune heights in deep flows and dune lengths are generally larger in shallow flows.
|Publication status||Published - 2012|
|Event||NCR-days 2012 - Arnhem, Netherlands|
Duration: 4 Oct 2012 → 5 Oct 2012
|Period||4/10/12 → 5/10/12|