Effect of casing on sound absorption characteristics of fine spherical granular material

To determine sound absorption coefficients of fine granular materials, the materials must be cased to suppress their flowability. In this study, effects of casing on the sound absorption coefficients of fine granular materials were investigated. The normal incidence sound absorption coefficients of cased hollow glass beads were measured using cylindrical impedance tubes. The measurement results demonstrated that the hollow glass beads present a...