22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-2.10.2
FLOW CONTROL DOWNSTREAM OF A BACKWARD FACING STEP
P. G. Spazzini, G. I. Uso, N. Zurlo, G. M. Di Cicca, M. Onorato
Politecnico di Torino, Italy
Keywords: separation, control, backfacing step, lebu
A simple LEBU-like device aimed at controlling
the separated flow field behind a backward
facing step, with special attention on its
unsteady properties, is described; the device
advantage is that it requires very small design
modifications and/or complications. Visualizations
of the controlled field are presented
along with wall hot-wire measurements.
The latter measurements provided information
about both the mean wall quantities (skin
friction) and unsteady properties (wall shear
stress fluctuations); RMS and spectra of these
fluctuations are presented, showing how the
distribution of fluctuation energy is influenced
by the presence of the manipulator. In particular,
specific positionings of the device allowed
to reduce wall unsteadinesses. To summarize
the outcomes of the work, although the
research is in its early stages, the results presented
here prove the viability of this way of
controlling separated flows.
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