At the onset of centrifugal instability in an open cavity flow
Résumé
This study deals with the experimental investigation of the onset of instability
in an open cavity flow, in the incompressible limit. Far below the development
of self-sustained oscillations, the first instability is three-dimensional on the
inner recirculating flow. We address the case of a cavity of a large span-wise
aspect ratio in which the side-wall effects are negligible. We study the pattern
selection at threshold as the stream-wise aspect ratio is varied and, for large
aspect ratios, we report the development of a second mode, which is quasisymmetric
to the primary mode.