Experimental investigations were earned out on flow induced acoustic resonance with tube banks composed of various tubes such as bare, solid fin, serrated fin, and plate-fin tubes.
Tube banks contained in ducts were connected to a silent wind tunnel and installed in an anechoic room. Sound emitted from the tube bank was measured by microphones on the duct wall and at the duct outlet.
The results clarified the effects of the fins on tube banks. In a wide longitudinal pitch of tube bank geometry, there were no great differences in resonant effect, although fins help to emit flow noise. In a narrow geometry, it was revealed that the characteristics of the fin participate in resonance and damping effect. With a complicated geometry, such as serrated fin and plate-fin tubes, there is a greater damping effect and less resonance is generated. In any case, the baffle plates dividing duct width could suppress the resonance.