Abstract
In the present paper the attention is focused on the relation between the vortex shedding phenomena and the velocity field around the tubes in tube banks. We measured a spectrum of velocity fluctuation, coherence function, gap velocity in the tube banks and sound pressure level at the duct exit in the case of a model of tube banks that has same pitch ratio as that of a boiler heat exchanger. When acoustic resonance has generated at the natural frequencies of the duct, which correspond to Strouhal number of 0.29,there are mainly two vortices which have Strouhal numbers about 0.29 and 0.22,in the tube banks and the wake of tube banks, respectively. These vortices are out of phase like Karman vortex shedding from a circular cylinder.
