| Summary: | The recirculations are essential in river engineering because they form silting zones and favour the
development of specific fauna and flora. This paper deals with the behaviour of the recirculation
zones occurring downstream the sudden expansion of an open channel. An Acoustic Doppler Velocimeter
is
used
to
measure
the
flow
details.
The mean flow property such as the length of the recirculation,
the
average
velocity
field
and
velocity
gradient
are
obtained.
Then the self-similarity of the
velocity profile is retrieved . The numerical simulation for the similar conditions are preformed with
the CFD software STAR CCM+. When compared with the experiments, the two approaches correspond
well in terms of length of recirculation zone and also regarding details such as the velocity
gradient profiles. Finally, the eddy viscosity concept is tested and the turbulent viscosity coefficient
are obtained along the streamwise axis for all flows.
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