A Study of Resonant-cavity and Fiberglass-filled Parallel Baffles as Duct SilencersNational Aeronautics and Space Administration, Scientific and Technical Information Branch, 1982 - Acoustical engineering - 63 pages |
Common terms and phrases
10-Foot Wind 120-Foot Wind Tunnel 4.9 STRAIGHT 406 mm thick 8000 ONE-THIRD OCTAVE acoustic impedance ACOUSTIC SECTION acoustic source Ames Research Center baffle length BAND CENTER FREQUENCIES cavity damping cavity resonance cavity shapes configuration cross modes diagonal septa Doelling downstream duct axis duct blockage duct lining DUCT SILENCERS duct width dynamic pressure equation exhaust simulation experimental fiberglass baffles fiberglass silencer fiberglass-filled baffles flow speed Hz Figure Hz third-octave bands impedance inlet simulation m/sec measured microphone mks rayls Moffett Field Mylar NASA OCTAVE BAND CENTER ONE-THIRD OCTAVE BAND open area PARALLEL BAFFLES parameters perforated skin predicting silencer reactance rectangular cavities resonant-cavity baffles resonant-cavity silencer Scharton shown in figure silencer attenuation silencer insertion loss silencer performance skin porosity Soderman solid skin sound attenuation sound field sound level sound propagation SOURCE STREAMWISE tail test section test-section tion transverse mode triangular cavities upstream vortex shedding walls wind speed