Author(s): Leslie Hopkinson; Theresa Wynn-Thompson

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Keywords: Boundary shear stress; Reynolds stress; turbulent flow; turbulent kinetic energy; vegetation

Abstract: In tidal environments, the boundary shear stress (BSS) is directly proportional to the turbulent kinetic energy, with a reported proportionality coefficient of 0.19. This coefficient was calculated using velocity time series to determine Reynolds stresses and, ultimately, to estimate the BSS. The coefficient has not been evaluated using direct measurements of BSS or for environments other than tidal systems. This laboratory flume study examines the validity of this relationship for a sloping streambank with and without vegetation. BSSs and near-bank Reynolds stresses were calculated using a constant temperature anemometer and velocity measurements, respectively. The coefficient ranged from 0.11 to 0.53 when calculated with the measured values of BSS, and 0.09 to 0.37 when calculated with Reynolds stresses. The variation was attributed to differences in turbulence generation, coefficient development, and instrumentation.

DOI: https://doi.org/10.1080/00221686.2012.684771

Year: 2012