Contribution
Study of the wide-band viscous sound absorption behavior of lattices of rigid cylinders
* Presenting author
Abstract:
The sound absorbing properties of lattices of hard cylinders in a fluid are mainly a consequence of viscous losses. This work makes use of homogenization to describe such behavior, backed by numerical calculations. The lattices are arranged first in slabs resulting in one-dimensional wave propagation, followed by approximately circular two-dimensional clusters. The study is carried out over wide-band frequency ranges, examining the influence of the filling fraction, effective length, lattice period and background medium properties. For each combination of parameters, it is shown that there always is an optimal value of the filling fraction (different from the maximum filling fraction) yielding maximum wide-band absorption. This is a result of the balance between wave reflection at the interface and the number and thickness of the spaces between cylinders where losses are concentrated. The results from this study help to better understand the behavior of materials with a similar structure, such as porous absorbers.