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Jet Surface Interaction-Scrubbing NoiseGeneration of sound due to scrubbing of a jet flow past a nearby solid surface is investigated within the framework of the generalized acoustic analogy theory. The analysis applies to the boundary layer noise generated at and near a wall, and excludes the scattered noise component that is produced at the leading or the trailing edge. While compressibility effects are relatively unimportant at very low Mach numbers, frictional heat generation and thermal gradient normal to the surface could play important roles in generation and propagation of sound in high speed jets of practical interest. A general expression is given for the spectral density of the far-field sound as governed by the variable density Pridmore- Brown equation. The propagation Green's function should be solved numerically starting with the boundary conditions on the surface and subject to specified mean velocity and temperature profiles between the surface and the observer. The equivalent sources of aerodynamic sound are associated with non-linear momentum flux and enthalpy flux terms that appear in the linearized Navier-Stokes equations. These multi-pole sources should be modeled and evaluated with input from a Reynolds-Averaged Navier-Stokes (RANS) solver with an appropriate turbulence model.
Document ID
20140002891
Acquisition Source
Glenn Research Center
Document Type
Contractor Report (CR)
Authors
Khavaran, Abbas (Vantage Partners, LLC Brook Park, OH, United States)
Date Acquired
April 14, 2014
Publication Date
September 1, 2013
Subject Category
Acoustics
Report/Patent Number
NASA/CR-2013-218090
E-18785
Funding Number(s)
WBS: WBS 473452.02.03.07.06.01.02
CONTRACT_GRANT: NNC12BA01B
Distribution Limits
Public
Copyright
Public Use Permitted.

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