EFFECTS OF PHYSICAL PARAMETERS OF CIRCULAR DUCT IN SHEAR FLOW ON SOUND ATTENUATION

Engineering prediction models of sound propagation in a circular duct with segmented liners in uniform flow and shear flow are established by means of the modal analysis method.The effects of the physical parameters,such as boundary layer thickness,mean flow Mach number,acoustic resistance,characteristic frequency of the facing sheet,cavity depth,and duct length on the in-duct sound attenuation have been determined for a numerical example.In addition,the test data of total sound attenuation in a duct with flow,published by other authors,have been used to verify the feasibility of the engineering prediction method provided.