Aeroacoustic sound generation in simple expansion chambers.
A method is presented for measuring the aeroacoustic source strength in ducts with flow at frequencies at which the wave motion can be considered substantially one-dimensional. The method is based on coherent power flux measurements using pairs of microphones positioned both upstream and downstream of the source region. The method is applied to a flow excited expansion chamber with aeroacoustic source measurements presented for chambers with a range of flow velocities and chamber lengths. The results indicate locked-on flow tones are generated in the chamber. The frequency of these locked-on flow tones is compared with that predicted using describing function theory applied to resonators with a grazing flow as well as that of other literature.
Institute of Sound and Vibration Research, University of Southampton, Southampton S017 1BJ, United Kingdom.
Emmet J
EJ
English
Keith R
KR
Holland
D000162:Acoustics; D000392:Air Movements; D000399:Air Pressure; D008962:Models, Theoretical; D009624:Noise, Transportation; D001335:Vehicle Emissions
D001335:Vehicle Emissions