Pressure Sources for a Wave Model of Jet Noise

An Acoustic Field Generated by Subsonic Jets at Low Reynolds Numbers

“…A significant contribution from the potential core to the radiated sound was observed at directions close to jet axis. Chan's (1974a) formula is in,good agreement with observations for 0.2 < Sh < 1.0 and e < 75°. the predicted power spectral density for the m = 0 mode overestimates by as much as 3 dB at high frequencies.…”

“…In the present study, the validity of Michalke's spectral theory was first verified entirely with the experimental data obtained by Chan (1976) and Yamamoto and Arndt (1977). Chan's (1974a) prediction formula, Eq. 3.2.5 for the single azimuth-frequency component of jet noise based on the Hicha1ke's expausionscheme was found to predict the power spectral density of the jet noise quite welL The predicted dinectivity of the radiated sound by the same formula is generally in good agreement with observations except at large emission angles.…”

“…26. Chan (1974a) proposed that this source' term can be written in terms of the fluctuating pressure according to the dilation theory of Ribner (1962). Furthermore, the experimental results obtained by Chan (1974b) for the instability pressure waves in an acoustically excited jet can be used to compute a pt'oper form for the' source function.…”

“…One of the practical ways to achieve this is to e:x:press this quantity in terms of the fluctuating pressu1:'e. For this purpose, Chan (1974a)…”

On turbulence and noise of an axisymmetric shear flow

“…Another possible sideway, which would by-pass some of the tremendously time-consuming correlation measurements, could be to introduce into the theory of suitable models for the longitudinal (nearly wavelike) and lateral correlations on the basis of already available experimental evidence and investigate the effect of moderate deviations from these model assumptions on the radiation pattern. A first step in this direction may be seen in a short note by Chan (1974b).…”