Flow induced acoustic resonance in in-line tube banks

Abstract

In the present paper the attention is focused on the relation between vortex shedding phenomena and acoustic resonance which occurred in the two-dimensional model of boiler. There were tube banks with in-line arrangement for small tube pitch ratio. We measured the sound pressure level, the phase delay of acoustic pressures, the spectrum of velocity fluctuation and the gap velocity. As a result, we found two peak frequencies of sound pressure level with different Strouhal numbers S t , mainly about 0.26 and 0.52. The noise of S t =0.26 was the resonance of transverse mode and S t =0.52 was longitudinal mode. The vortex shedding of S t =0.15 was generated inside the tube banks without acoustic resonance. As gap velocity increased, we observed that the peak level of spectrum was weak and broad-banded. The onset velocity of the acoustic resonance of longitudinal mode was lower than that of transverse mode.

Foreground and Background Components in Separable Complex Systems

“…Separated spectra can be observed in published data in many mechanical vibration experiments. As examples, one can cite vibrations in the body [1], seat [2], gearbox [3] and external mirrors [4] of automobiles, cavitation in pumps [5], in ship-borne antennas [6], in operating wind turbines [7], in heat exchanger tube banks [8] and in vortex-induced vibrations in tensioned steel risers [9]. There are of course many other examples.…”