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Uniformly distorted turbulence, i.e., turbulence with superimposed
uniform mean velocity gradient, is simplified model of many
existing engineering turbulent flows, for example, the flow
around a running ship propeller and the turbulent flow in
contraction (expansion) duct. At the same time, the response
of turbulence to the imposed distortion is a challenge for
current turbulence models (Reynolds Average Models, Large
Eddy Simulation, etc).
A new facility
is being developed to study the properties of turbulence
under rapid distortion. One piston is moving up and down
inside one water tank. The motion of the piston is programmed
so as to apply uniform distortion over the flow in the test
section, which is near central bottom of the tank. Two groups
of active grids are running at high speed to generate isotropic
turbulence in the test section. Both Particle Image Velocimetry
(PIV) and Holographic Particle Image Velocimetry (HPIV)
will be used to get detailed velocity field of test section.
Recent effort has been put into the designing, assembling
and testing of the hardware.
This research
project is sponsored by Office of Naval Research (ONR)
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