Characteristics of internal- and jet-noise radiation from a multi-lobe, multi-tube suppressor nozzle tested statically and under flight simulation

1980 ◽  
Author(s):  
K. AHUJA ◽  
M. SALIKUDDIN ◽  
H. PLUMBLEE, JR.
Keyword(s):  
Jet Noise ◽  
Flight Simulation ◽  
Noise Radiation

scholarly journals ON APPLICABILITY OF ADDITIVE TECHNOLOGY IN PRODUCING NOZZLES FOR JET NOISE INVESTIGATIONS

Akustika ◽  
2019 ◽  
Vol 34 ◽  
pp. 180-184 ◽  
Author(s):  
Igor Khramtsov ◽  
Evgeniya Cherenkova ◽  
Vadim Palchikovskiy ◽  
Oleg Kustov
Keyword(s):  
Sound Pressure ◽  
Small Diameter ◽  
Jet Noise ◽  
Additive Technology ◽  
Noise Radiation ◽  
Fused Deposition ◽  
Air Jet ◽  
Power Spectral ◽  
Noise Measurements ◽  
Jet Velocities

The split-type conical nozzles with replaceable exit sections with diameters of 30, 40 and 50 mm were designed and produced from steel by machine turning. In addition, the replaceable output parts of the nozzles with the same diameters were produced by additive technology (fused deposition manufacturing) from ABS plastic. In the acoustic anechoic chamber, the noise measurements of a single-stream cold air jet for all the nozzles at jet velocities in the range of 0.3-0.7 Mach numbers were carried out. The noise measurements were performed on distance of 2 m from the center of the nozzle exit section at angles from 30 to 105o. For different directions of noise radiation and different velocities of the jet, the power spectral density and overall sound pressure level were determined. The obtained results demonstrates that the jet noise for nozzles with diameter of 40 and 50 mm from steel and ABS plastic differs by no more than 1 dB, which is within the measurement error for these types of experiments. The nozzles with diameter 30 mm have a higher difference in noise, which can be explained by the more sensitivity of a nozzle with a small diameter to the deviations of geometric parameters when it produced by additive technology.

scholarly journals Supersonic Jet Noise Reductions Predicted With Increased Jet Spreading Rate

1998 ◽  
Vol 120 (3) ◽  
pp. 471-476 ◽  
Author(s):  
Milo D. Dahl ◽  
Philip J. Morris
Keyword(s):  
Supersonic Jet ◽  
Jet Noise ◽  
Spreading Rate ◽  
Operating Conditions ◽  
Instability Wave ◽  
Noise Levels ◽  
Radiation Model ◽  
Radiated Noise ◽  
Noise Radiation ◽  
Mixing Noise

In this paper, predictions are made of noise radiation from single, supersonic, axisymmetric jets. We examine the effects of changes in operating conditions and the effects of simulated enhanced mixing that would increase the spreading rate of the jet shear layer on radiated noise levels. The radiated noise in the downstream direction is dominated by mixing noise and, at higher speeds, it is well described by the instability wave noise radiation model. Further analysis with the model shows a relationship between changes in spreading rate due to enhanced mixing and changes in the far field radiated peak noise levels. The calculations predict that enhanced jet spreading results in a reduction of the radiated peak noise level.

Aerodynamic noise

1971 ◽  
Vol 48 (3) ◽  
pp. 593-603 ◽  
Author(s):  
M. J. Fisher ◽  
M. V. Lowson
Keyword(s):  
Jet Noise ◽  
Diffraction Theory ◽  
Aerodynamic Noise ◽  
Jet Flows ◽  
Focus Attention ◽  
Dominant Effect ◽  
Noise Radiation ◽  
Rotor Noise ◽  
Inflow Conditions ◽  
Degree Of Order

A symposium on aerodynamic noise was held at Loughborough University from 14 to 17 September 1970 under the sponsorship of the Royal Aeronautical Society and the British Acoustical Society. The objective of the meeting was to focus attention on unsolved theoretical and experimental problems which will require attention over the next few years. Areas which were covered included jet noise, nonlinear acoustics, rotor noise, and diffraction theory. The symposium was successful in bringing together several new themes in aerodynamic noise research. The most significant of these were the existence of a degree of order in turbulent jet flows, and the dominant effect of inflow conditions on rotor noise radiation. In addition an improved and unified basis for jet noise theory seems to be evolving.

scholarly journals Modelling of jet noise: a perspective from large-eddy simulations

2019 ◽  
Vol 377 (2159) ◽  
pp. 20190081 ◽  
Author(s):  
Guillaume A. Brès ◽  
Sanjiva K. Lele
Keyword(s):  
Acoustic Waves ◽  
Jet Noise ◽  
Large Eddy Simulations ◽  
Acoustic Analogy ◽  
Theme Issue ◽  
Noise Radiation ◽  
Numerical Studies ◽  
Large Eddy ◽  
Turbulent Jet Flow ◽  
Nozzle Shape

In the last decade, many research groups have reported predictions of jet noise using high-fidelity large-eddy simulations (LES) of the turbulent jet flow and these methods are beginning to be used more broadly. A brief overview of the publications since the review by Bodony & Lele (2008, AIAA J. 56 , 346–380) is undertaken to assess the progress and overall contributions of LES towards a better understanding of jet noise. In particular, we stress the meshing, numerical and modelling advances which enable detailed geometric representation of nozzle shape variations intended to impact the noise radiation, and sufficiently accurate capturing of the turbulent boundary layer at the nozzle exit. Examples of how LES is currently being used to complement experiments for challenging conditions (such as highly heated pressure-mismatched jets with afterburners) and guide jet modelling efforts are highlighted. Some of the physical insights gained from these numerical studies are discussed, in particular on crackle, screech and shock-associated noise, impingement tones, acoustic analogy models, wavepackets dynamics and resonant acoustic waves within the jet core. We close with some perspectives on the remaining challenges and upcoming opportunities for future applications. This article is part of the theme issue ‘Frontiers of aeroacoustics research: theory, computation and experiment’.

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