Effects of Plate Spacing and Downstream Plate Length on the Acoustic ResonanceExcited by Flow past Two Plates in Tandem in a Duct

摘要

The effects of plate spacing and downstream plate chord on the acoustic resonancegenerated by vortex shedding from tandem plates in a duct were investigated. The resonant sound amplitude and frequency were measured for various combinations of plate spacing and downstream plate chord. The test rig, a blow down open circuit wind tunnel specifically designed for the study of flow induced acoustic resonances, is described, together with the experimental procedure. Results are given and discussed. It is found that the plate spacing affected both the amplitude of the sound produced, and the velocity range over which the resonance was excited. The plate chord affected only the amplitude of the sound produced. The models of other investigators, developed to explain the effects of place spacing, are shown to have shortcomings. A hypothesis is proposed which is consistent with the observed variation with plate spacing in the velocity range over which the resonance occurred.