Efficient modeling and experimental validation of acoustic resonances in three-dimensional rectangular open cavities

The goal of this paper is to investigate the acoustic resonances of a three-dimensional open cavity by a fast and efficient method in the time domain. This method models the time response in any point as the convolution of the source waveform with the impulse response of the cavity, which, in turn, is obtained as a sequence of attenuated and delayed impulses coming, the first from the real, and the subsequent from the mirror imaged sources (Image Source Model). This method, which main advantages with respect to others that work in the frequency domain are that the results for all frequencies can be calculated at once, the time domain data is recovered directly, and the computational cost does not increase with frequency, can easily provide the frequency response at each point of the cavity by Fourier transform. From these frequency responses, the relevant resonances of the cavity can simply be obtained. Illustration and experimental validation of the proposed method is presented by its application to a rectangular open cavity.