Print Email Facebook Twitter Transverse Momentum Exchange Induced by Large Coherent Structures in a Vegetated Compound Channel Title Transverse Momentum Exchange Induced by Large Coherent Structures in a Vegetated Compound Channel Author Truong, S. H. (Thuyloi University) Uijttewaal, W.S.J. (TU Delft Environmental Fluid Mechanics) Date 2019 Abstract In floodplains of vegetated channels, transverse exchange processes of mass and momentum are of primary importance as these are directly linked to the river bank stability, sedimentation, and nutrient transport. Despite its importance, knowledge about this phenomenon is still incomplete especially in the context of the presence of the large horizontal coherent structures (LHCSs). As a result, although various exchange models have been developed, their applicability in different circumstances is still unclear as their validity is usually restricted to a narrowly ranging experiment data set. A proper model for this exchange in a compound channel geometry with or without vegetation is lacking. In order to obtain more insight, a laboratory experiment of a shallow flow field in a compound vegetated channel has been conducted. A quadrant analysis of the Reynolds shear stresses has been applied to study the connection between the cycloid flow events induced by the LHCSs and transverse momentum exchange in the channel. It is suggested that local variability leads to differences in the transverse exchange of momentum. Furthermore, the experimental data were used to verify state-of-the-art momentum exchange models. As the limitations of those models were analyzed, for the first time a hybrid eddy viscosity model based on the occurrence of LHCSs and the presence of vegetation was proposed and validated using a variety of experimental data sets. The results suggest that the transverse momentum exchange can be well modeled with the new eddy viscosity model for quite a range of different setups and scenarios by varying only a coefficient of proportionality β, which is related to the transverse slope between the main channel and the floodplain. To reference this document use: http://resolver.tudelft.nl/uuid:b0b8706f-2618-4467-91d5-5fc60319f984 DOI https://doi.org/10.1029/2018WR023273 ISSN 0043-1397 Source Water Resources Research, 55 (1), 589-612 Part of collection Institutional Repository Document type journal article Rights © 2019 S. H. Truong, W.S.J. Uijttewaal Files PDF Truong_et_al_2019_Water_R ... search.pdf 5.08 MB Close viewer /islandora/object/uuid:b0b8706f-2618-4467-91d5-5fc60319f984/datastream/OBJ/view