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On the Role of Sidewalls in the Transition From Straight to Sinuous Bedforms
Author(s) -
Zgheib N.,
Balachandar S.
Publication year - 2019
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 - 10.1029/2019gl084098
Subject(s) - bedform , flume , geology , turbulence , open channel flow , mechanics , sinuosity , slip (aerodynamics) , reynolds number , flow (mathematics) , geotechnical engineering , geomorphology , geometry , sediment transport , sediment , physics , thermodynamics , mathematics
We present results from direct numerical simulation (DNS) on the transition from straight-crested to sinuous-crested bedforms. The numerical setup is representative of turbulent open channel flow over an erodible sediment bed at a shear Reynolds number of . The immersed boundary method (IBM) accounts for the presence of the bed. The simulations are two-way coupled such that the turbulent flow can erode and modify the bed, and in turn, the bed modifies the overlying flow. Coupling from the flow to the bed occurs through the Exner equation, while back coupling from the bed to the flow is achieved by imposing the no-slip and no-penetration condition at the immersed boundary. The simulation setup is similar to that by Zgheib et al. [2018a] except for the presence of sidewalls to better mimic laboratory flume conditions. Sidewalls are observed to significantly increase bedform sinuosity.