The origin of the well-known ‘grain size gap’ within range 1–10 mm in fluvial gravels is explored a laboratory experiment to ascertain effect hydraulic sorting. A widely graded sand/gravel mixture was fed into flume containing bed composed same sediment mixture. rate feed varied but water flow remained constant throughout at that sustained size-selective bedload transport with negligible suspen...

Abstract Linear stability analysis is used to investigate the behavior of small perturbations a uniform flow in straight channel with an erodible bed composed by unisize sediment. A shallow-water model employed and bedload sediment transport assumed. The mathematical structure linear problem, terms eigenvalues their associated eigenvectors explored detail information gathered on wavespeed growt...

We present a fully coupled 2DV morphodynamic model, implemented in OpenFOAM® that is capable of simulating swash-zone morphodynamics sandy beaches. The hydrodynamics are described by the Reynolds-averaged Navier–Stokes (RANS) equations with k?? turbulence model and Volume Fluid (VoF) approach for discriminating between air water. Sediment transport terms bedload suspended load transport. show d...

We consider a deterministic model of landscape evolution through the mechanism of overland flow over an erodible substrate, using the St. Venant equations of hydraulics together with the Exner equation for hillslope erosion. A novelty in the model is the allowance for a nonzero bedload layer thickness, which is necessary to distinguish between transport limited and detachment limited sediment r...

We are developing a three-dimensional numerical model that implements algorithms for sediment transport and evolution of bottom morphology in the coastal-circulation model Regional Ocean Modeling System (ROMS v3.0), and provides a two-way link between ROMS and the wave model Simulating Waves in the Nearshore (SWAN) via the ModelCoupling Toolkit. The coupled model is applicable for fluvial, estu...

The existence of both water and sediment at the bed of ice streams is well documented, but there is a lack of fundamental understanding about the mechanisms of ice, water and sediment interaction. We pose a model to describe subglacial water flow below ice sheets, in the presence of a deformable sediment layer. Water flows in a rough-bedded film; the ice is supported by larger clasts, but there...

Abstract The Gangetic Plains comprise steep gravelly river channels that transition to low gradient sandy 10-40 km downstream of the mountain front. This “gravel-sand transition" is characterized by an abrupt greater-than-one-order-of-magnitude drop in both and sediment grain size, suggesting a degree long-term stability. However, stratigraphic record gravel-sand Miocene Siwalik Group demonstra...

Our long terms goals are to understand sediment transport processes, the relevant physical forcing processes and the resulting morphologic evolution of river mouths and tidal inlets and shoals. Specific goals include understanding bedform characteristics (ripple to sandwave and sandbar scale) in relation to wave-and current-forced mean and turbulent flow. OBJECTIVES 1. Measure the currents, hyd...