Quality factor and boundary-layer attenuation of lower order modes in acoustic cavities

M. Bruneau , Ch. Garing , H. Leblond

Some acoustic devices make use of closed cavities, filled with gas, the dimensions of which are of the same order of magnitude as the acoustic wavelength and the walls of which are perfectly rigid. To know the acoustic response of such small cavities, driven by a mechanical or a thermodynamical source, one needs to take into account the damping processes. In this case they are essentially due to viscous and thermal effects in the boundary layers and are described as a finite apparent acoustic impedance depending on the modes. In this paper, the sound field is determined in a « rectangular » enclosure excited by a point source and is described by a modal theory. The Q-factor is calculated and its properties are discussed and compared with experimental results. The agreement is quite good.

Mots clés: acoustic field; acoustic impedance; acoustic resonators; Q factor

Domaines: Articles anciens

M. Bruneau, Ch. Garing, H. Leblond. Quality factor and boundary-layer attenuation of lower order modes in acoustic cavities. Journal de Physique, 1985, 46 (7), pp.1079-1085. ⟨10.1051/jphys:019850046070107900⟩. ⟨jpa-00210051⟩