Large-scale structures and growth of a flat plate compressible wake

Experiments conducted on a flat plate wake in a compressible flow at Mach 2 are described. Large-scale organized motions are revealed both in the separating boundary layer upstream and in the wake downstream. The organized motions in the wake contained within them embeded vortex structures, whose periodicity was found to be weak. The broadband spectra contained a distinct frequency with a Strouhal number of 0.3. The study of mean flow characteristics showed that some qualitative similarity exists in the near- and intermediate-wake regions. The relative Mach number distribution showed the compressibility effects to be small.