Abstract
In the present paper the attention is focused on the effects of cavity in in-line tube banks on acoustic resonance which occurred in the two-dimensional model of boiler. As a result, we found many peak frequencies of sound pressure level with different Strouhal numbers, mainly about S_t=0.15, 0.26 and 0.52. The existence of cavities in in-line tube banks caused the resonance of S_t=0.15. The vortex shedding of S_t=0.l5 were generated inside of cavity and the tube banks without acoustic resonance. It was easy to generate acoustic resonance when there were cavities of tube pitch ratio of 2.5〜3.5 in in-line tube banks.
