Large scale modulation of high frequency acoustic waves in periodic porous media

• DOI: 10.1121/1.4763553
• Publication Date: 2012-12-07T12:56:08Z
• Authors: Claude Boutin; Antoine Rallu; Stephane Hans
• Keywords: Homogenization; Modulation (music)

This paper deals with the description of modulation at large scale high frequency acoustic waves in gas saturated periodic porous media. High frequencies mean local dynamics pore and therefore absence separation usual sense homogenization. However, although pressure is spatially varying pores (according to eigenmodes), mode amplitude can present a modulation, thereby introducing another type which asymptotic multi-scale procedure applies. The approach first presented on network inter-connected Helmholtz resonators. equations governing modulations carried by eigenmodes, close their eigenfrequency, are derived. number cells carrying defined parameter modeling. In second part, developed for media perfect gas. Using "multicells" condition, one obtains family waves. significant difference between simple multiple evidenced discussed. features (anisotropy, width band) also analyzed.