The contribution of M.J.M Römkens to this article was prepared as part of his duties as a United States Federal Government Employee.
Grain transport mechanics in shallow overland flow
Article first published online: 10 AUG 2009
Copyright © 2009 John Wiley & Sons, Ltd.
Special Issue: The National Sedimentation Laboratory: 50 years of soil and water research in a changing agricultural environment
Volume 2, Issue 3, pages 248–256, September 2009
How to Cite
Prasad, S.N., Suryadevara, M. R. and Römkens, M.J.M. (2009), Grain transport mechanics in shallow overland flow. Ecohydrol., 2: 248–256. doi: 10.1002/eco.64
- Issue published online: 25 SEP 2009
- Article first published online: 10 AUG 2009
- Manuscript Accepted: 28 APR 2009
- Manuscript Received: 14 JAN 2009
- shallow overland flow;
- continuum transport model;
- granular dispersive model;
- particle velocity;
- photonic probes
A physical model based on continuum multiphase flow is described to represent saltating transport of grains in shallow overland flows. The two-phase continuum flow of water and sediment considers coupled StVenant-type equations. The interactive cumulative effect of grains is incorporated by a dispersive stress term. The mean fluid thrust on the particle in the saltation layer of grains is expressed in terms of a slip velocity. The continuum model leads to the unexpected, but an interesting result is that particle velocity increases with the solid concentration. This increase predicts monotonic behaviour leading to overestimates of particle velocity at higher sediment concentration. To improve the predictions, grain dynamic equations, which incorporate bed collision, are analysed. The analysis leads to an improved model for predicting saltation height. Incorporation of the results in the continuum model yields a velocity-concentration relationship that is consistent with experimental observations for increasing concentration. Laboratory flume experiments explore the evaluation of various parameters from the measured particle velocities by photonic probes. Copyright © 2009 John Wiley & Sons, Ltd.