NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Effects of boundary layer refraction and fuselage scattering on fuselage surface noise from advanced turboprop propellersAn acoustic disturbance's propagation through a boundary layer is discussed with a view to the analysis of the acoustic field generated by a propfan rotor incident to the fuselage of an aircraft. Applying the parallel flow assumption, the resulting partial differential equations are reduced to an ordinary acoustic pressure differential equation by means of the Fourier transform. The methods used for the solution of this equation include those of Frobenius and of analytic continuation; both yield exact solutions in series form. Two models of the aircraft fuselage-boundary layer system are considered, in the first of which the fuselage is replaced by a flat plate and the acoustic field is assumed to be two-dimensional, while in the second the fuselage is a cylinder in a fully three-dimensional acoustic field. It is shown that the boundary layer correction improves theory-data comparisons over simple application of a pressure-doubling rule at the fuselage.
Document ID
19840035189
Document Type
Conference Paper
Authors
Mcaninch, G. L.
(NASA Langley Research Center Hampton, VA, United States)
Rawls, J. W., Jr.
(Kentron International, Inc. Hampton, VA, United States)
Date Acquired
August 12, 2013
Publication Date
January 1, 1984
Subject Category
Acoustics
Report/Patent Number
AIAA PAPER 84-0249
Distribution Limits
Public
Copyright
Other
No Preview Available