scholarly journals Design and Demonstration of a New Small-Scale Jet Noise Experiment

2012 ◽  
Author(s):  
Ryan Fontaine ◽  
Brock Bobbitt ◽  
Gregory Elliott ◽  
Joanna Austin ◽  
Jonathan Freund
Keyword(s):  
Jet Noise ◽  
Small Scale ◽  
Noise Experiment

Comparison of GPU CABARET, RANS and RANS/ILES High Resolution Method Solutions for the CoJen Jet Noise Experiment

2019 ◽  
Author(s):  
Anton P. Markesteijn ◽  
Sergey A. Karabasov ◽  
Vasily Gryazev ◽  
Ruslan S. Ayupov ◽  
Leonid Benderskiy ◽  
...  
Keyword(s):  
High Resolution ◽  
Jet Noise ◽  
Resolution Method ◽  
Noise Experiment ◽  
High Resolution Method

The Effect of Chevrons on Crackle: Engine and Scale Model Results

2011 ◽  
Author(s):  
Steve Martens ◽  
John T. Spyropoulos ◽  
Zac Nagel
Keyword(s):  
High Performance ◽  
Jet Noise ◽  
Scale Model ◽  
Small Scale ◽  
Mixing Enhancement ◽  
Noise Component ◽  
Acoustic Environment ◽  
Jet Mixing ◽  
Near Term ◽  
The Impact

GE and the USN continue to work together to find and develop practical techniques to reduce jet noise on tactical aircraft such as the F/A-18 E/F/G. Noise is an important issue for the Navy because of the harsh acoustic environment induced during operations of these aircraft on aircraft carriers and the impact to communities around Naval Air Bases and training sites. The noise generated by these systems is predominantly the noise generated by the exhaust plume due to the low bypass ratio of the engine and very high exhaust jet velocities. The main components of this jet noise are the jet mixing, shock and crackle noise. The present paper reports on progress, following Reference [1] with the F/A-18 E/F/G jet noise reduction program, which is currently focused on the USN near term goal of up to 3 dB reduction in the peak directivity direction. This goal also includes the reduction of the shock and crackle noise components. These goals are currently being pursued with nozzle plume mixing enhancement employing mechanical chevrons. These chevrons can be incorporated in the production version as a redesign of the F414 nozzle seals and do not involve the introduction of additional parts to the nozzle. This paper focuses on the effect of chevrons on the crackle noise component both in full scale on the F404 engine, and in small scale on the F414 engine nozzle in the twin configuration. The paper aims to make the case that this effect, which was first observed during ground engine testing of prototype chevrons, is a beneficial one in reducing/eliminating crackle which continues to be prevalent in high performance tactical aircraft engines today.

On the noise sources of the unsuppressed high-speed jet

1971 ◽  
Vol 50 (1) ◽  
pp. 21-31 ◽  
Author(s):  
K. A. Bishop ◽  
J. E. Ffowcs Williams ◽  
W. Smith
Keyword(s):  
Reynolds Number ◽  
High Speed ◽  
Large Scale ◽  
Jet Noise ◽  
Jet Flow ◽  
Scale Model ◽  
Small Scale ◽  
Noise Sources ◽  
Supersonic Transport ◽  
Scale Turbulence

The paper describes an interpretation of jet-noise theory and scale-model experiments to highlight physical properties of jet-noise sources at very high speed. The study is prompted by current efforts to suppress the noise of supersonic transport aircraft.The principal noise sources are shown to be very large-scale wave-like undulations of the jet flow that travel downstream at supersonic speed for a distance of several jet diameters. These motions are relatively well ordered and are probably more akin to recognizable instabilities of a laminar flow than the confused small-scale turbulence. Because of this we postulate a model of the noise generating motions as the instability products of a jet flow of low equivalent Reynolds number. This Reynolds number is based on an eddy viscosity and can be further reduced by artificially increasing the small-scale turbulence level. This step would tend to stabilize the flow and inhibit the formation of large-scale noise producing eddies.

A Hybrid LES/RANS Calculation of Subsonic, Supersonic Hot Jet Noise

2007 ◽  
Author(s):  
Xiaodan Cai ◽  
Foluso Ladeinde
Keyword(s):  
Large Scale ◽  
Supersonic Jet ◽  
Jet Noise ◽  
Small Scale ◽  
Complex Geometries ◽  
High Fidelity ◽  
Acoustic Analogy ◽  
Turbulent Structures ◽  
Analogy Method ◽  
Arbitrary Complex

In this paper, pure RANS and hybrid LES/RANS procedures have been investigated for the simulation of jet noise from subsonic and supersonic, hot jets. The aerodynamic predictions from the RANS calculations agree well with experimental measurements. It is emphasized that the RANS-based acoustic analogy method used is incapable of capturing the sound characteristics at small jet angles, which are dominated by the sound radiated from large-scale turbulent structures. The hybrid LES/RANS approach investigated by Shur et al is examined. The preliminary results for a subsonic, hot jet (Set Point 46 in Tanna’s experiment) have shown that this method can capture, satisfactorily, the near-filed velocity and pressure signatures induced by large-scale turbulent structures. It is our goal to establish the feasibility and advantages of using a high-fidelity tool for predicting both small scale and large-scale supersonic jet noise with arbitrary complex geometries and under realistic flight conditions.

Scaling and extrapolating small-scale in-flow wind tunnel jet noise to full-scale flyover jet noise

1997 ◽  
Author(s):  
Christopher Allen ◽  
Paul Soderman ◽  
Christopher Allen ◽  
Paul Soderman
Keyword(s):  
Wind Tunnel ◽  
Jet Noise ◽  
Full Scale ◽  
Small Scale

High order harmonics anomaly of jet screech

2018 ◽  
Vol 32 (15) ◽  
pp. 1850154
Author(s):  
Zhe Chen ◽  
Jiu Hui Wu ◽  
A-Dan Ren ◽  
Xin Chen
Keyword(s):  
Fundamental Frequency ◽  
Sound Pressure ◽  
Pressure Ratio ◽  
Jet Noise ◽  
Pressure Level ◽  
High Order ◽  
Small Scale ◽  
Shock Cell ◽  
Nozzle Pressure Ratio ◽  
Nozzle Pressure

Imperfectly expanded supersonic jets under strong screech could generate both fundamental screech tones and multiple tones at the harmonics of the fundamental frequency. The paper compares the fundamental frequency of jets from both AR = 3 (Aspect Ratio) and AR = 4 rectangular nozzles, and conducts analysis of harmonics on Sound Pressure Level (SPL) spectrums of jet noise. The research suggests that the fundamental frequency of the first two- or three-order harmonics increases when the Nozzle Pressure Ratio (NPR) decreases, whereas the highest order harmonic decreases when the NPR decreases. Besides, the paper also observes the differences between the highest order harmonics and other harmonics that have never been reported before. Further analysis on flow field schlieren of AR = 3 nozzle indicates that the highest order harmonic is the outcome of interaction between second shock-cell and nonlinear instable wave. The revolution of these high order harmonics can provide guidance for the prevention of small-scale structure fatigue damage. Moreover, the distribution test of the noises is also carried out to verify the high order harmonics anomaly, and indicate that the jet noise spreads mainly towards downstream while screech towards upstream. In addition, the broadband shock-associated noise spreads vertical to the jet flow and exhibits the feature of directivity.

Sign in / Sign up

Export Citation Format

Share Document