Flow-induced pulsations in pipe systems with closed side branches: study of the effectiveness of detuning as remedial measure

Flow-induced pulsations in resonant pipe systems with two closed side branches in cross configuration are considered. These pulsations, commonly observed in many technical applications, are self-sustained aeroacoustic oscillations driven by the instability of the flow along the closed branches. Detuning of the acoustic resonator is often considered as a possible remedial measure. Although this countermeasure appears to be very effective for double side branch systems in cross configuration with anechoic boundary conditions of the main pipe, its effectiveness has not been assessed for different boundary conditions. The significance of the acoustic boundary conditions of the main pipe has been studied by means of experiments conduced on double side branch systems presenting two acoustically reflecting boundaries of the main pipe. While pulsations are often a nuisance, the double side branch system can also be used as a powerful sound source.