Effect of Flow Induced Acoustic Resonance on Vortex Shedding from Staggered Tube Banks

In the present paper, attention was focused on the relation between vortex shedding phenomena and acoustic resonance in staggered tube banks. As a result, three types of vortex shedding were found with different Strouhal numbers (S_t), 0.29, 0.22, and 0.19, in cases without resonance. When resonance was generated at the natural frequency of the duct, 342.5Hz, at a gap velocity of 39.2m/s, two types of vortex shedding were found with different frequencies, mainly about 342.5Hz (S_t=0.29) and 262.5Hz (S_t=0.22), inside the tube banks. The velocity fluctuation and periodicity of the vortex shedding were the most intense in the wake of the second row of tube banks. A short baffle plates was effective for preventing the generation of acoustic resonance of the transverse mode if it was installed at the correct place where velocity fluctuation and periodicity of vortex shedding were most intense.