Parametric study of acoustic windows using a Green’s Function transfer matrix method

Abstract

The Green’s function dependent transfer matrix method was applied to model sound transmission loss of a plenum window with a given configuration. The analytically calculated transmission loss reasonably followed that of the experimental data obtained from a previous study. The troughs in the calculated transmission loss spectra were found aligning well with the natural frequencies of the acoustic modes inside the plenum chamber. Vectorization of the calculations shows a 10-fold acceleration in computation, enabling desktop evaluation of transmission losses of plenum window systems with various configurations. Utilizing the analytical model, a parametric study of varying the three crucial design parameters, including the gap width, the overlapping length and the area ratio, between the outlet and inlet openings of the plenum window was conducted. The results demonstrated that increases in the latter two design parameters would improve the transmission loss performance of the plenum window at low frequencies, while increasing the gap width would compromise its transmission loss performance. Also, an increase in the overlapping length would widen the frequency range coverage with elevated transmission loss performance.