Title: Flow Induced Acoustical Resonance in Staggered Tube Arrays
Abstract:A staggered array of closely packed rigid tubes has been tested, in a wind tunnel of varying the flow velocity, to investigate the conditions under which acoustical resonances do or do not materialize...A staggered array of closely packed rigid tubes has been tested, in a wind tunnel of varying the flow velocity, to investigate the conditions under which acoustical resonances do or do not materialize. Among the aspects which have been investigated are: the Strouhal numbers at which flow periodicities occur; the relation between these Strouhal numbers and those at which acoustical resonances occur; the effect of the Reynolds numbers and the longitudinal tube spacing on the occurrence of acoustical resonance.This investigation has shown that:1. The acoustic resonance can be excited at a frequency well removed from that of vortex shedding. The results also show evidence of both phenomena existing, simultaneously at different frequencies.2. The acoustic resonances behavior is consistent with that of a self excited system.3. An alternative model of this phenomenon provides a better procedure for avoiding these resonances in closely packed tube banks.On the basis of these findings and the findings from a similar investigation into vortex induced tube vibration it is proposed that tube vibration and acoustic vibration are treated as different mechanisms. Hence the guidelines presented in this paper should be followed to avoid the occurrence of acoustic vibration.Read More