Numerical simulations are used to investigate the resonant instabilities in the flow past an open cavity. The compressible Navier-Stokes equations are solved directly (no turbulence model) for two-dimensional cavities with laminar boundary layers upstream. The computational domain is large enough to directly resolve a portion of the radiated acoustic field. The results show a transition from a shear layer mode, for shorter cavities and lower Mach numbers, to a wake mode for longer cavities and higher Mach numbers. The shear layer mode is well characterized by Rossiter modes. The wake mode is characterized instead by a large-scale vortex shedding with Strouhal number independent of the Mach number. The vortex shedding causes the boundary layer to periodically separate upstream of the cavity. The wake mode oscillation is similar to that reported by Gharib and Roshko (J. Fluid Mech., 177, 1987) for incompressible flow with a laminar upstream boundary layer. The results suggest that laminar separation upstream of the cavity edge is the cause of the transition to wake mode.
|Original language||English (US)|
|State||Published - 1999|
|Event||Aeroacoustics Conference and Exhibit, AIAA/CEAS 1999 - Bellevue, United States|
Duration: May 10 1999 → May 12 1999
|Other||Aeroacoustics Conference and Exhibit, AIAA/CEAS 1999|
|Period||5/10/99 → 5/12/99|
All Science Journal Classification (ASJC) codes