Basic design considerations and theoretical analysis of double-reverberant chamber duct lining test facilities

Basic design criteria for establishing the geometry of a duct liner test facility are evolved. A theoretical model of the facility is established, yielding the acoustic behavior of the test section alone. The measurements necessary for the interpretation of the test section performance are discussed. Finally, models of the attenuation in the test section are presented for correlation with theoretical models of acoustically treated ducts. Two principal features of the analysis are that it includes the following effects: (i) that of flow on the acoustic fields as well as on the liner absorption; (ii) that of possible variations in the impedance of the terminating chamber—e.g. it could be anechoic rather than reverberant.