Theory of Sound Propagation in a Flow Duct Lined with Annular Segments of PorousMaterial

摘要

A theory is presented to calculate acoustic modes in a circular flow duct linedwith porous material. The porous material is divided into annular segments by a rigid structure, which prevents axial sound propagation from one segment into the other. Single modes cannot exit in such a configuration, but it is shown that approximate solutions of the eigenvalue problem can be constructed. A numerical example is given and compared with special cases from the literature.