Shear-driven cavity flows With semi-closed walls

This paper presents numerical and experimental results of investigations on the three-dimensional impulsive flow past a resonant cavity at a laminar Reynolds number, Re <8,000. The geometry consisted of a squared cross section, with spanwise aspect-ratio equal to 3, and a cavity inlet 1/4 of its length. Numerical simulations were carried out for a flow time exceeding 6 minutes, and laboratory experiments for over 30 minutes. The findings of the numerical study indicate that the flow is not steady, but tends asymptotically to a steady state solution, in which the large eddies have dissipated. The flow remains substantially symmetric, even when perturbations are introduced. The Taylor-Görtler-like vortices that establish at the centre of the cavity have a relatively short time span. The laboratory investigation does not support this finding at long flow times. Other vortical structures present in the cavity include hairpin vortices, end-wall vortices, and filament vortices.