A study on finite amplitude standing waves in stepped acoustic resonator

Investigation of finite amplitude standing waves generated by boundary driving in the stepped acoustic resonator has been carried out both theoretically and experimentally to derive an appropriate tool to design resonators that have characteristics suitable for specific applications such as a microphone cali-bration system with a higher-pressure level. Initially, a modified resonance condition is proposed, which is deduced from the transfer matrix method and the characteristics of the standing wave resonator. The predictions of the resonance frequencies in a cylindrical resonator are in excellent agreement with those obtained by analytic formula in previous studies. Then, the modified resonance condition is applied to calculate the resonance frequencies of a stepped resonator. The boundary driving is provided by a piston at the open end. The resonant response in the cylindrical and stepped resonator, including the pressure amplitudes, the pressure waveform and the distribution of pressure amplitude along the axis, is calcu-lated numerically by the finite volume method, which is a preliminary prediction of finite amplitude standing waves in the resonators. The calculated results of the stepped resonator are verified in the experiment, in which a stepped acoustic resonator is connected to a loudspeaker functioning as the piston.(c) 2022 Elsevier Ltd. All rights reserved.