Abstract
The present paper focuses on the effect of air jets on acoustic absorption coefficient of a perforated thin plate with cavity. We discussed the influences of plate thickness, opening ratio of small holes, hole diameter, shape of cross-section of hole, and number of holes on acoustic absorption characteristics experimentally. The normal incidence absorption coefficient was calculated from the measured transfer function by using transfer function methods. The air flow rate is controlled from 0 to 100 l/min. As a result, the frequency characteristics of the acoustic absorption coefficient showed a maximum value at the local frequency. As the opening rate of small holes increased, the peak level of acoustic absorption coefficient increased at the flow rate of 100 l/min. As the hole diameter decreased with same opening ratio, the acoustic absorption coefficient increased at the higher frequency range.
