Artículo
Application of a roughness-length representation to parameterize energy loss in 3-D numerical simulations of large rivers
Sandbach, Steven D.; Lane, Stuart N.; Hardy, Richard J.; Amsler, Mario Luis
; Ashworth, Philip J.; Best, James L.; Nicholas, Andrew P.; Orfeo, Oscar
; Parsons, Daniel R.; Reesink, Arjan; Szupiany, Ricardo Nicolas
Fecha de publicación:
12/2012
Editorial:
American Geophysical Union
Revista:
Water Resources Research
ISSN:
0043-1397
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Recent technological advances in remote sensing have enabled investigation of the morphodynamics and hydrodynamics of large rivers. However, measuring topography and flow in these very large rivers is time consuming and thus often constrains the spatial resolution and reach-length scales that can be monitored. Similar constraints exist for computational fluid dynamics (CFD) studies of large rivers, requiring maximization of mesh- or grid-cell dimensions and implying a reduction in the representation of bedform-roughness elements that are of the order of a model grid cell or less, even if they are represented in available topographic data. These "subgrid" elements must be parameterized, and this paper applies and considers the impact of roughness-length treatments that include the effect of bed roughness due to "unmeasured" topography. CFD predictions were found to be sensitive to the roughness-length specification. Model optimization was based on acoustic Doppler current profiler measurements and estimates of the water surface slope for a variety of roughness lengths. This proved difficult as the metrics used to assess optimal model performance diverged due to the effects of large bedforms that are not well parameterized in roughness-length treatments. However, the general spatial flow patterns are effectively predicted by the model. Changes in roughness length were shown to have a major impact upon flow routing at the channel scale. The results also indicate an absence of secondary flow circulation cells in the reached studied, and suggest simpler two-dimensional models may have great utility in the investigation of flow within large rivers
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Articulos(INALI)
Articulos de INST.NAC.DE LIMNOLOGIA (I)
Articulos de INST.NAC.DE LIMNOLOGIA (I)
Citación
Sandbach, Steven D.; Lane, Stuart N.; Hardy, Richard J.; Amsler, Mario Luis; Ashworth, Philip J.; et al.; Application of a roughness-length representation to parameterize energy loss in 3-D numerical simulations of large rivers; American Geophysical Union; Water Resources Research; 48; 12; 12-2012; 1-21
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