The Effects of Surfaces on the Aerodynamics and Acoustics of Jet Flows

Aircraft noise mitigation is an ongoing challenge for the aeronautics research community. In response to this challenge, low-noise aircraft concepts have been developed that exhibit situations where the jet exhaust interacts with an airframe surface. Jet flows interacting with nearby surfaces manife...

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Bibliographic Details
Published inNASA Center for AeroSpace Information (CASI). Conference Proceedings
Main Authors Smith, Matthew J, Miller, Steven A E
Format Conference Proceeding
LanguageEnglish
Published Hampton NASA/Langley Research Center 27.05.2013
Subjects
Acoustic noise
Acoustics
Aerodynamic characteristics
Aerodynamic noise
Aerodynamics
Aeronautics
Aircraft
Aircraft noise
Airframes
Computational fluid dynamics
Dimensionless numbers
Jet exhaust
Mathematical models
Noise prediction (aircraft)
Nozzles
Particle image velocimetry
Reynolds averaged Navier-Stokes method
Velocity measurement
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Summary:Aircraft noise mitigation is an ongoing challenge for the aeronautics research community. In response to this challenge, low-noise aircraft concepts have been developed that exhibit situations where the jet exhaust interacts with an airframe surface. Jet flows interacting with nearby surfaces manifest a complex behavior in which acoustic and aerodynamic characteristics are altered. In this paper, the variation of the aerodynamics, acoustic source, and far-field acoustic intensity are examined as a large at plate is positioned relative to the nozzle exit. Steady Reynolds-Averaged Navier-Stokes solutions are examined to study the aerodynamic changes in the field-variables and turbulence statistics. The mixing noise model of Tam and Auriault is used to predict the noise produced by the jet. To validate both the aerodynamic and the noise prediction models, results are compared with Particle Image Velocimetry (PIV) and free-field acoustic data respectively. The variation of the aerodynamic quantities and noise source are examined by comparing predictions from various jet and at plate configurations with an isolated jet. To quantify the propulsion airframe aeroacoustic installation effects on the aerodynamic noise source, a non-dimensional number is formed that contains the flow-conditions and airframe installation parameters.