Transport enhancement in acoustically excited cavity flows, part 1: Nonreactive flow diagnostics

Acoustically driven, nonreactive flow processes in a two-dimensional dump combustor cavity were explored experimentally. Particle image velocimetry in the device was used to quantify the time-dependent, phase-locked velocity field in the cavity, Cavity operation during external acoustic excitation and during natural (undriven) operating conditions was explored, Interrogation of this flowfield showed quantifiable increases in inlet core/jet width, enhanced rates of entrainment between jet and recirculation regions, and increased jet rms velocity fluctuations during external forcing at frequencies corresponding to resonant longitudinal modes of the device. No such enhancement was observed during off-resonance external excitation. These results suggest that external 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.