Interaction Between Main Line Standing Waves and Side Branch Resonance Frequencies

Acoustic standing waves may be established in main gas delivery lines and are caused by resonance in branch lines. The branch line resonance frequency is normally determined from the geometry of the branch. Data are presented that show the branch line standing wave couples with the main line standing wave, and a range of side branch resonance frequencies are possible, with multiple frequencies existing in the side branch at the same time in some cases. This phenomenon is important to gas delivery systems where acoustic frequencies and loads must be predicted to facilitate design of the system components.