Morfey, C.L., Tester, B.J. and Powles, C.J.
Numerical and asymptotic Lilley equation solutions for the Goldstein jet-noise source model
In Proceedings of the 13th AIAA/CEAS Aeroacoustics Conference (28th AIAA Aeroacoustics Conference).
American Institute of Aeronautics and Astronautics. 28 pp, .
Full text not available from this repository.
Far-field sound radiation from model sources in a jet shear layer has been calculated
numerically using the stationary phase approximation. The jet column is modeled as an
axisymmetric parallel shear flow, so jet spreading is neglected. For this simplified model,
analytical predictions are provided in the low and high frequency limits, k0?<<1 and k0?>>1
(k0 = acoustic wavenumber; ? = shear layer thickness). The low-frequency analytic result
matches the numerical prediction quite closely up to k0? = 1; it accounts quantitatively for
the observed strong scattering of quadrupole radiation by the mean velocity and density
profiles in the jet. Further work is required to establish bounds of validity for the stationaryphase
approximation, and to assess available high-frequency (k0?>1) approximations for the
cone of silence region.
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