Experimental study on sound absorption characteristics of granular material: Influence of lateral constraints of casing

Tsuruha Takumasa, Yoshinari Yamada, Makoto Otani, Yasushi Takano
2019 Proceedings of the ICA congress  
The sound absorption characteristics of flowable granular materials may vary owing to lateral constraints. In order to clarify the effect of lateral constraints on the sound absorption characteristics of granular materials, the normal incidence sound absorption coefficients of hollow glass beads filled in cylindrical containers of different diameters were measured. The measurement results demonstrated that the sound absorption coefficients varied depending on the diameters of the containers. As
more » ... the containers. As the diameter increased while the thickness of the granular material was constant, the first peak frequency of the sound absorption coefficient shifted towards a lower frequency. The amount of shift due to diameter expansion increased with larger thickness of the granular material. These results suggest that the sound absorption characteristics of granular materials can be controlled by adjusting the distance between the constraining walls without changing the thickness of the granular materials.
doi:10.18154/rwth-conv-239009 fatcat:e2tcajwbvracdjprlp3qiboqxm