Acoustic damping of an annular tail-pipe under mean flow conditions

A damping device, consisting of an annular tail-pipe, has been developed. It is applicable in situations wherein acoustic damping is required in combination with low flow resistance. The device consists of a central tube surrounded by a narrow slit. The central tube has an acoustic mass which impedance increases with frequency while the slit resistance remains constant. When the frequency has been increased sufficiently, a considerable part of...