The Prediction and Analysis of Jet Flows and Scattered Turbulent Mixing Noise about Flight Vehicle Airframes

Jet flows interacting with nearby surfaces exhibit a complex behavior in which acoustic and aerodynamic characteristics are altered. The physical understanding and prediction of these characteristics are essential to designing future low noise aircraft. A new approach is created for predicting scatt...

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Bibliographic Details
Published inNASA Center for AeroSpace Information (CASI). Reports
Main Author Miller, Steven A E
Format Report
LanguageEnglish
Published Hampton NASA/Langley Research Center 01.07.2014
Subjects
Acoustic noise
Acoustics
Aerodynamic characteristics
Aerodynamic noise
Aerodynamics
Aircraft components
Aircraft noise
Airframes
Computational fluid dynamics
Dimensionless numbers
First principles
Flat plates
Flight vehicles
Fluid flow
Fluid-structure interaction
Green's functions
Low noise
Noise
Noise prediction (aircraft)
Noise propagation
Plates (structural members)
Ray tracing
Reynolds averaged Navier-Stokes method
Turbulent mixing
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Summary:Jet flows interacting with nearby surfaces exhibit a complex behavior in which acoustic and aerodynamic characteristics are altered. The physical understanding and prediction of these characteristics are essential to designing future low noise aircraft. A new approach is created for predicting scattered jet mixing noise that utilizes an acoustic analogy and steady Reynolds-averaged Navier-Stokes solutions. A tailored Green's function accounts for the propagation of mixing noise about the airframe and is calculated numerically using a newly developed ray tracing method. The steady aerodynamic statistics, associated unsteady sound source, and acoustic intensity are examined as jet conditions are varied about a large flat plate. A non-dimensional number is proposed to estimate the effect of the aerodynamic noise source relative to jet operating condition and airframe position.The steady Reynolds-averaged Navier-Stokes solutions, acoustic analogy, tailored Green's function, non-dimensional number, and predicted noise are validated with a wide variety of measurements. The combination of the developed theory, ray tracing method, and careful implementation in a stand-alone computer program result in an approach that is more first principles oriented than alternatives, computationally efficient, and captures the relevant physics of fluid-structure interaction.