Features of the Operation of Powered Resonance Tube Actuators: Experiments and Simulations

There has been a recent surge of interest in powered resonance tube actuators for flow control applications. Additional features of powered resonance tube actuators (both experiments and simulations) are presented in this paper. A Powered Resonance Tube (PRT) is a device based on aeroacoustics principles, capable of producing intense perturbation levels for use in active flow control. The PRT described here is capable of producing frequencies ranging from 1600 to 15,000 Hz at amplitudes as high as 160 dB near the source. Our detailed experiments aimed at understanding the PRT phenomenon are complemented by improved direct numerical simulations. We provide a detailed characterization of the unsteady pressures in the nearfield of the actuator using phase averaged pressure measurements. The measurements revealed that propagating fluctuations were biased towards the upstream direction (relative to the supply jet) for some frequencies. However, this feature depended on the frequency at which the device was operated. The simulations that were performed earlier at a Reynolds number 490 times lower than that in the experiment have been refined. The current simulations are performed at 49 times lower than that in the experiments and show that a finer scale structure develops at higher Reynolds numbers and a more regular oscillation is present at low Reynolds numbers.