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A Two‐Layer Turbulence‐Based Model to Predict Suspended Sediment Concentration in Flows With Aquatic Vegetation
Author(s) -
Tseng ChienYung,
Tinoco Rafael O.
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl091255
Subject(s) - turbulence , turbulence kinetic energy , turbulence modeling , boundary layer , environmental science , shear velocity , sediment , vegetation (pathology) , sediment transport , geology , hydrology (agriculture) , open channel flow , flow (mathematics) , shear stress , large eddy simulation , soil science , mechanics , geomorphology , geotechnical engineering , medicine , physics , pathology
Traditional bed shear stress‐based models (e.g., Rouse model) derived from the classic parabolic profile of eddy viscosity in open‐channel flows fail to accurately predict suspended sediment concentration (SSC) in flows with aquatic vegetation. We developed a two‐layer, turbulence‐based model to predict SSC profiles in emergent vegetated flows. Turbulence generated from vegetation, bed, and coherent structures caused by stem‐bed‐flow interaction are considered into the near‐bed turbulent kinetic energy (TKE) to calculate the effective bed shear velocity,u b eff * . The model, validated by experimental data, further showed that the thickness height of the near‐bed layer (effective bottom boundary layer), H b , varies with flow velocity and canopy density. Two additional models are provided to estimate H b andu b eff * . The model is expected to provide critical information to future studies on sediment transport, landscape evolution, and water quality management in vegetated streams, wetlands, and estuaries.