Title

Self-preserving characteristics in wall-wake flow downstream of an isolated bedform

Document Type

Research Article

Publication Title

Environmental Fluid Mechanics

Abstract

The results of an experimental study on the turbulence characteristics in flow over and downstream of an isolated bedform are presented. The vertical profiles of time-averaged streamwise velocity, Reynolds stresses and turbulent kinetic energy (TKE) fluxes at different horizontal locations over and downstream of a bedform are shown to demonstrate their variations. The experimental results signify a flow acceleration, separation and deceleration over the stoss-side, at the crest and in the leeside of a bedform. In addition, in the wall-wake region (far downstream of the bedform), the defects (uninterrupted upstream value minus downstream value at a given vertical distance) in time-averaged streamwise velocity, Reynolds shear stress (RSS), turbulence intensities and TKE fluxes demonstrate the self-preserving characteristics in their individual vertical profiles when they are scaled by their individual peak defects. For scaling the vertical distance to achieve the self-preserving characteristics, the defect profiles of velocity were scaled by the half-width of peak velocity defect, those of RSS and turbulence intensities by the half-width of peak RSS defect and those of TKE fluxes by the half-width of individual peak TKE flux defects. The peak defects of all the parameters lessen, as one moves toward the downstream, recovering their uninterrupted upstream profiles.

First Page

1119

Last Page

1139

DOI

10.1007/s10652-020-09744-8

Publication Date

8-1-2020

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