On the number of tube rows required to study cross-flow induced vibrations in tube banks

Careful experiments in which a triangular array of tubes with a pitch ratio of 1·375 was used have been undertaken to determine the minimum number of tube rows required to study flow induced vibration phenomena typical of a tube bank. Individual tube responses were monitored to examine the effects of different numbers of upstream and downstream tube rows. It was found that the critical tubes for fluid-elastic instability are in the third and fourth rows. From the point of view of studying vibrations induced by turbulence, vorticity phenomena and fluid-elastic instability, it is recommended that six tube rows be used.