Morphology and flow fields of three-dimensional dunes, Rio Parana, Argentina: Results from simultaneous multibeam echo sounding and acoustic Doppler current profiling

Details

Serval ID
serval:BIB_4F3A98D4F1E0
Type
Article: article from journal or magazin.
Collection
Publications
Title
Morphology and flow fields of three-dimensional dunes, Rio Parana, Argentina: Results from simultaneous multibeam echo sounding and acoustic Doppler current profiling
Journal
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
Author(s)
Parsons DR, Best JL, Orfeo O, Hardy RJ, Kostaschuk R, Lane SN
ISSN
0148-0227
Publication state
Published
Issued date
12/2005
Volume
110
Number
F4
Notes
ISI:000234248700002
Abstract
[1] Most past studies of river dune dynamics have concentrated on
two-dimensional (2-D) bed forms, with constant heights and straight
crest lines transverse to the flow, and their associated turbulent flow
structure. This morphological simplification imposes inherent
limitations on the interpretation and understanding of dune form and
flow dynamics in natural channels, where dune form is predominantly
three-dimensional. For example, studies over 2-D forms neglect the
significant influence that lateral flows and secondary circulation may
have on the flow structure and thus dune morphology. This paper details
a field study of a swath of 3-D dunes in the Rio Parana, Argentina. A
large (0.35 km wide, 1.2 km long) area of dunes was surveyed using a
multibeam echo sounder (MBES) that provided high-resolution 3-D detail
of the river bed. Simultaneous with the MBES survey, 3-D flow
information was obtained with an acoustic Doppler current profiler (
ADCP), revealing a complicated pattern of dune morphology and
associated flow structure within the swath. Dune three-dimensionality
appears intimately connected to the morphology of the upstream dune,
with changes in crest line curvature and crest line
bifurcations/junctions significantly influencing the downstream dune
form. Dunes with lobe or saddle-shaped crest lines were found to have
larger, more structured regions of vertical velocity with smaller
separation zones than more 2-D straight-crested dunes. These results
represent the first integrated study of 3-D dune form and mean flow
structure from the field and show several similarities to recent
laboratory models of flow over 3-D dunes.
Web of science
Open Access
Yes
Create date
03/02/2011 14:41
Last modification date
20/08/2019 14:05
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