E3S Web Conf.
Volume 40, 2018River Flow 2018 - Ninth International Conference on Fluvial Hydraulics
|Number of page(s)||7|
|Section||Fluid mechanics and sediment processes|
|Published online||05 September 2018|
Lagrangian modeling of bedload movement via the impulse entrainment method
Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, TN, USA
2 Hydraulics and Sedimentation Laboratory (HSL), The University of Tennessee, Knoxville, TN, USA
* Corresponding author: firstname.lastname@example.org
At low shear stresses merely above incipient conditions, the characteristic travel patterns of bedload particles remain difficult to predict due to intermittent movement. At these conditions, particles rest, are entrained into the flow when sufficient momentum transfer from near-bed turbulence occurs, and then come to rest again. The overarching goal of this research is to close the critical gaps related to intermittent movement in order to allow for Lagrangian modeling of bedload at near incipient conditions. Thereby, the specific objectives of the present work are to predict the statistics of (1) the particle resting time, tR, and (2) the magnitude of hydrodynamic momentum transfer (or impulse) during entrainment, Ient. To predict these statistics, we employed the conceptual framework of the impulse entrainment method and predicted impulse statistics by simulating turbulent time series realizations with a generic, regime-based streamwise velocity spectrum. Model validation was carried out by directly comparing simulation results with published experimental impulse and particle entrainment statistics. Model predictions showed that an increase in stress was correlated with a sharp decrease in the average tR and an increase in Ient.
© The Authors, published by EDP Sciences, 2018
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (http://creativecommons.org/licenses/by/4.0/).
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