Experimental study of double‑cavity flow
Résumé
The flow through two facing, identical cavities
(double-cavity) is characterized experimentally, as the
inflow velocity and the distance between the cavities is
varied. Standard 2D2C particle image velocimetry measurements
in the spanwise mid-plane provide information
on the instantaneous and mean velocity flow fields. Laser
Doppler velocimetry measurements at several points in the
double-cavity domain reveal the global character of the
streamwise fluctuating velocity spectra. The flow is characterized
based on time series, recorded in the shear layer of
one of the cavities, for a wide range of inflow velocities and
intercavity distances. In a detailed spectral study, we show
how the shear layer spectra get affected when the two cavities
are brought closer together. Based on the experimental
data, a temporal local linear stability analysis was carried
out, which was able to explain why the frequency peaks
for close intercavity distances broaden and move to higher
Strouhal numbers.