Effect of Bulk-Reacting Liners on Wave Propagation in Ducts

An analysis is presented for the effect of bulk-reacting liners on the wave propagation and attenuation in twodimensional and circular ducts carrying sheared mean flow. The wave propagation in an isotropic porous material lining the walls is coupled with wave propagation in the duct. The results indicate that the porosity and structure factor of the porous material have a non-negligible effect on the attenuation rate. The attenuation rate does not increase monotonically with either the liner thickness or resistivity. Considerable error may be introduced by treating a bulk-reacting liner as a point-reacting liner.

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