Print Email Facebook Twitter Sound transmission in and radiation from hard-walled annular ducts related to fan engine inlets Title Sound transmission in and radiation from hard-walled annular ducts related to fan engine inlets Author Laan, J.N. Institution National Aerospace Laboratory NLR Date 1975-11-06 Abstract In this report the sound propagation in a hard-walled annular duct of finite length is investigated. The individual modal solutions so found are described. The main properties which are calculated in the present report, are the modal intensity and the modal far field directivity pattern. The modal intensity is determined by the rate of mode excitation. Mode excitation by various sound sources is discussed. Subject Acoustic propertiesAcoustic ductsSound propagationAcoustic excitationSound fieldsAircraft noiseRadiation sourcesPropagation modesFar fieldsDirectivityWave equationsAcoustic impedanceSound wavesNoise shieldingAcoustic rfeflectionCompressor rotors To reference this document use: http://resolver.tudelft.nl/uuid:468f6b60-a2aa-48a0-9728-37565c920805 Publisher Nationaal Lucht- en Ruimtevaartlaboratorium Access restriction Campus only Source NLR-TR 75144 U Part of collection Aerospace Engineering Reports Document type report Rights (c)1975 National Aerospace Laboratory NLR Files campus only