Self-Excited Acoustic Resonance of Isolated Cylinders in Cross-Flow

Self-excited acoustic resonance is a design concern in many engineering applications such as tube bundles of heat exchangers and boilers. Since this phenomenon is not yet fully understood, it can be dangerously unpredictable. Due to the complexity of the flow-sound interaction mechanisms in tube bundles, the simplified cases of a single cylinder and two cylinders in various arrangements, tandem and staggered, are investigated in some detail. A summary of these investigations is presented in the current paper. It is found that the aeroacoustic response of two-tandem and side-by-side cylinders in cross-flow can be considerably different from that of a single cylinder under similar flow conditions. Moreover, for the case of two tandem cylinders, the acoustic resonance is excited over two different ranges of flow velocity; the pre-coincidence and the coincidence resonance ranges. The pre-coincidence acoustic resonance phenomenon is found to be similar to the acoustic resonance mechanism of in-line tube bundles.