STUDY OF NONLINEAR ACOUSTIC CHARACTERISTICS OF PERFORATED CONSTRUCTIONS AT HIGH SOUND PRESSURE LEVELS

Based on the theory concerning the nonlinear acoustic resistance of an orifice presented by Zhao Song-ling et al., the authors derived the expressions about the nonlinear acoustic resistance of the perforated constructions for the both circumstances of normal incidence in a standing wave tube and sidebranch incidence in a progressive wave tube. This paper points out that taking the nonlinear resistance into account, both the absorption coefficient of the perforated absorbing construction and the transmission loss of the resonance-type muffler will depend on the incidence sound pressure.
Experiments carried out in a standing wave tube and a progressive wave tube of high intense sound separately. In the experiments the highest incidence sound pressure level approached about 155 dB （ref. 2×10^-5 Pa）.
The experimental results coincide with the theoretical prediction rather well.
In order to facilitate the practical application of the theory, this paper also provides several critical conditions showing the nonlinear behaviour of acoustic resistance.