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A rough isolated dune was placed over a gravel bed with d50 = 2.5 mm and 3-D velocity
components were measured at upstream, above, and downstream of the dune. The isolated
dunal structure was then replaced by a series of dunes with different sizes and another set of
experiments were conducted. With the isolated dunal structure, the data were analyzed for the
time-averaged turbulence flow characteristics over and downstream of it. Analysis of the
experimental data reveals that the time-averaged streamwise velocity, Reynolds shear stress
(RSS), Reynolds normal stresses (RNSs), and streamwise and vertical turbulent kinetic energy
fluxes preserve the wall-wake similarity downstream of a dunal structure. However, over the
dune the similarity was not possible due to the difference in bed levels and water depths. Data
from beds with series of dunes were analyzed for turbulent kinetic energy, three-dimensional
bursting, and turbulence anisotropy.

Related papers:

1. S. Sarkar, S. Dey (2019): “Turbulence in wall-wake flow downstream of an isolated
dune.” XXXVIII International School of Hydraulics, 21-24 May 2019 ŁĄCK,
POLAND.
2. S. Dey, S. Sarkar (2019): “Turbulent length scales and Reynolds stress anisotropy in
wall-wake flow downstream of an isolated dunal bedform.” XXXVIII International
School of Hydraulics, 21-24 May 2019 ŁĄCK, POLAND.
3. S. Sarkar, S. Dey: “Self-preserving characteristics in wall-wake flow downstream of
an isolated bedform.” (Communicated).

(Sankar Sarkar)

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