ボイラにおける管群からの渦放出と気柱共鳴現象との関係

抄録

In the present paper the attention is focused on relation between acoustic resonance and vortex shedding from in-line tube banks. We have examined the characteristics of acoustic resonance generated from tube banks with tube pitch ratio of 4.0, 3.5, 2.8, 2.0, 1.8, 1.7, 1.6 and 1.4 in the flow direction. At the tube pitch ratio in the flow direction of 4.0-2.8, the acoustic resonance of low order mode in the transverse direction occurred. The alternative vortex were clearly formed in the tube banks. At the tube pitch ratio in the flow direction of 2.0, the acoustic resonance of high order mode in the flow direction occurred. The symmetric vortex were formed in the tube banks. At the tube pitch ratio in the flow direction of 1.8-1.4, as the tube pitch ratio in the flow direction decreased, the acoustic resonance of longitudinal mode occurred. The alternative vortex and symmetric vortex were formed in the tube banks. The onset velocity of longitudinal mode were lower than that of transverse mode at the small tube pitch ratios.