Jet noise from coaxial nozzles over a wide range of geometric and flow parameters

Abstract

Free field pure jet noise data were taken for a large range of coaxial nozzle configurations. The core nozzles were circular (1 to 4 in. diam.) and plug types. The fan to core area ratio varied from 0.7 to 43.5, while the velocity ratio typically varied from 0 to 1. For most cases the two nozzles were coplanar but large axial extensions of either nozzle were also tested. Correlation of the data resulted-in a simple procedure for estimating ambient temperature subsonic coaxial jet noise spectra over a wide range of geometric and flow parameters.

Multidisciplinary conceptual design optimization of aircraft using a sound-matching-based objective function

“…Specifically, Fink's model (Fink 1977) is used to compute the airframe noise, and Heidmann's method (Heidmann 1975) is applied for the fan and compressor noise. The jet noise is estimated from a database of recorded data (Olsen and Friedman 1974) and the buzz-saw noise is calculated following Morfey and Fisher (1970). Atmospheric attenuation (Sutherland et al 1974), ground reflection (Attenborough 1992) and doppler effect (e.g., Ruijgrok 2000) are also taken into account.…”

Lip noise generated by flow separation from nozzle surfaces

“…Another example of flow separation caused noise (based on data taken in Ref. 4) is shown on Fig. 28, 4 coarlal nozzle with a mixing chamber formed by a ^rralght outer nuzzle extension pipe of length 1 i o -2 and 6 is sketched on Fig.…”

“…The results were integrated to obtain the overall sound pressure level, OASPL, and the sound power level spectrum, PWL, as described in Ref. 4. Data for the additional noise due to flow separation (SPLc and OASPLc) were computed from the 1/3 octave SPL spectra by removing the small jet noise contribution.…”

“…The rig used for the larger nozzle data (i.e., 10 cm nozzles and larger) was one line of the coaxial nozzle rig described in Ref. 4, which used larger but similar flow Lines and hardware.…”

Investigation of Noise From Full-Scale High Bypass Engine and Blown Flap System

“…G-ENGINE ALONE 80 1 1 I 3000 4000 5000 6000 7000 8000 9000 CORRECTED THRUST, FN 6 , LB (e) CO-PLANAR DECAYER WISHROUD.…”