TRANSPORT ENHANCEMENT IN ACOUSTICALLY EXCITED CAVITY FLOWS, PART 1 - NONREACTIVE FLOW DIAGNOSTICS

Acoustically driven, nonreactive flow processes in a two-dimensional d ump combustor cavity were explored experimentally. Particle image velo cimetry in the device was used to quantify the time-dependent, phase-l ocked velocity field in the cavity, Cavity operation during external a coustic excitation and during natural (undriven) operating conditions was explored, Interrogation of this flowfield showed quantifiable incr eases in inlet core/jet width, enhanced rates of entrainment between j et and recirculation regions, and increased jet rms velocity fluctuati ons during external forcing at frequencies corresponding to resonant l ongitudinal modes of the device. No such enhancement was observed duri ng off-resonance external excitation. These results suggest that exter nal acoustic excitation at resonant modes can result in enhanced mass and momentum transport within the cavity Bow, providing a potentially powerful method for active Bow central.