Abstract
Flow-induced acoustic resonance in a piping system containing closed coaxial side branches was investigated experimentally. Dominant frequency and arbitrary scale power of the frequency spectrum as functions of the flow rate in the main pipe was obtained by a microphone. The results reveal that the dominant frequency was locked to five different values with relatively high acoustic powers. These fixed frequencies indicate that five different acoustic modes are generated when the flow rate in the main pipe increased gradually. The lock-in frequencies were in good agreement with the results calculated from an empirical equation. The time-averaged velocity fields corresponding to the second hydrodynamic oscillation mode were also demonstrated at various phase of the acoustic cycle.
