BASE-PRESSURE COEFFICIENTS FOR FLOWS AROUND RECTANGULAR-PLATES

The flow around long rectangular plates can be modified by acoustic fo rcing. The leading-edge vortex shedding is locked to the sound frequen cy over abroad range of flow velocities. Close to a critical acoustic Strouhal number, significant drops in the mean base pressure coefficie nt may occur, depending on the plate chord. It is hypothesised that th e plate chord changes the position in the acoustic phase at which the leading-edge vortices arrive at the trailing edge. Interference with t he trailing-edge vortex shedding may then be responsible for the signi ficant variation in mean base pressure coefficient. This situation in not observed for flows around plates with no leading-edge shedding.