Abstract
The last several decades have witnessed the development of both capacity and non-capacity models for fluvial sediment transport. While recent investigations of the multiple timescales of fluvial processes have substantiated the understanding of conditional applicability of capacity models, the extent to which a capacity model differs from a non-capacity model remains to be unravelled. This paper presents a comparative investigation of one-dimensional
capacity and non-capacity models. As a corollary to the theoretical analyses of the multiple timescales of fluvial processes, this study demonstrates that bed load transport can adapt to local flow sufficiently rapidly and, accordingly, a capacity model is applicable. However, as bed evolution modifies the flow considerably, a non-capacity model is needed if the flow is to be properly resolved in addition to bed load transport. Furthermore, it takes a long
time and space for suspended sediment transport to adapt to capacity. Therefore non-capacity modelling is critical for suspended sediment transport, whereas a capacity model may result in considerable errors at best and become
ill-posed at worst because of the requirement for extra boundary conditions. The findings of this work should facilitate the physically enhanced development and applications of mathematical river models.
capacity and non-capacity models. As a corollary to the theoretical analyses of the multiple timescales of fluvial processes, this study demonstrates that bed load transport can adapt to local flow sufficiently rapidly and, accordingly, a capacity model is applicable. However, as bed evolution modifies the flow considerably, a non-capacity model is needed if the flow is to be properly resolved in addition to bed load transport. Furthermore, it takes a long
time and space for suspended sediment transport to adapt to capacity. Therefore non-capacity modelling is critical for suspended sediment transport, whereas a capacity model may result in considerable errors at best and become
ill-posed at worst because of the requirement for extra boundary conditions. The findings of this work should facilitate the physically enhanced development and applications of mathematical river models.
Original language | English |
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Pages (from-to) | 193-211 |
Number of pages | 19 |
Journal | Proceedings of the ICE - Water Management |
Volume | 165 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 Apr 2012 |
Keywords
- hydraulics & hydrodynamics
- mathematical modelling
- river engineering