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Why do published models for fluvial and estuarine morphodynamics use unrealistic representations of the effects of transverse bed slopes?

Tritthart, Michael ; Vanzo, Davide 1; Chavarrías, Victor; Siviglia, Annunziato; Sloff, Kees; Mosselman, Erik
1 Institut für Wasser und Umwelt (IWU), Karlsruher Institut für Technologie (KIT)

Abstract:

The sediment transport direction is affected by the bed slope. This effect is of crucial importance for two- and three-dimensional modelling of the interaction between the flow of water and the alluvial bed. It is not uncommon to find applications of numerical morphodynamic models in the literature that exaggerate the effects of transverse bed slopes on sediment transport compared to results from laboratory experiments. We investigate mathematically the consequences of such an approach, and we analyse through numerical simulations different explanations for the need to apply deviating values. The study reveals that the reason often lies in the setup of the numerical models, such as the choice of mesh resolution or the necessity to comply with specific aspects of the numerical scheme. The missing or inadequate implementation of physical processes in the model is another cause. All of these effects can be compensated by artificial diffusion added through the bed slope effect coefficients. Since increased diffusion strongly alters the physical processes of self-formed bed morphology, we recommend that modellers address the root causes of inflated erosion and deposition. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000176073
Veröffentlicht am 08.11.2024
Originalveröffentlichung
DOI: 10.1016/j.advwatres.2024.104831
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Wasser und Umwelt (IWU)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 11.2024
Sprache Englisch
Identifikator ISSN: 0309-1708
KITopen-ID: 1000176073
Erschienen in Advances in Water Resources
Verlag Elsevier Masson
Band 193
Seiten Art.-Nr.: 104831
Nachgewiesen in Scopus
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