TY - JOUR
T1 - Hydraulic resistance in mixed bedrock-alluvial meandering channels
AU - Fernández, Roberto
AU - Vitale, Alejandro J.
AU - Parker, Gary
AU - García, Marcelo H.
N1 - Publisher Copyright:
© 2020 International Association for Hydro-Environment Engineering and Research.
PY - 2021
Y1 - 2021
N2 - We present an experimental analysis of hydraulic roughness variations due to changes in alluvial cover in a mixed bedrock-alluvial meandering channel with larger bedrock roughness than alluvial roughness. Three sets of experiments were conducted in a highly sinuous flume: one with bare bedrock, and two with enough sediment to cover 21% and 78% of the bedrock respectively. We compare our results with data from experiments previously conducted in the same flume with flat- and smooth-bed, and data from experiments with fully alluvial conditions. Our results show that: (1) hydraulic resistance in a mixed bedrock-alluvial channel changes with the degree of alluviation; (2) hydraulic resistance is greater for bare-bedrock conditions, and decreases as sediment supply increases; (3) if bedforms appear, hydraulic resistance may be larger than for bare bedrock conditions due to form drag; (4) fluctuations in alluvial cover due to freely-migrating bars lead to instantaneous changes in hydraulic resistance.
AB - We present an experimental analysis of hydraulic roughness variations due to changes in alluvial cover in a mixed bedrock-alluvial meandering channel with larger bedrock roughness than alluvial roughness. Three sets of experiments were conducted in a highly sinuous flume: one with bare bedrock, and two with enough sediment to cover 21% and 78% of the bedrock respectively. We compare our results with data from experiments previously conducted in the same flume with flat- and smooth-bed, and data from experiments with fully alluvial conditions. Our results show that: (1) hydraulic resistance in a mixed bedrock-alluvial channel changes with the degree of alluviation; (2) hydraulic resistance is greater for bare-bedrock conditions, and decreases as sediment supply increases; (3) if bedforms appear, hydraulic resistance may be larger than for bare bedrock conditions due to form drag; (4) fluctuations in alluvial cover due to freely-migrating bars lead to instantaneous changes in hydraulic resistance.
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U2 - 10.1080/00221686.2020.1780489
DO - 10.1080/00221686.2020.1780489
M3 - Article
AN - SCOPUS:85089504445
SN - 0022-1686
VL - 59
SP - 298
EP - 313
JO - Journal of Hydraulic Research
JF - Journal of Hydraulic Research
IS - 2
ER -