Abstract
In the present paper the attention is focused on the effect of cavity length in in-line tube banks with small tube spacing 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 acoustic resonance of S_t=0.15 was generated in in-line tube banks with cavities of tube pitch ratio of 2.11〜3.44. The velocity fluctuation and periodicity of the vortex shedding were the most intense inside of cavities of tube pitch ratio of 2.78〜3.44. It was easy to generate acoustic resonance in this case.
