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Open AccessJournal ArticleDOI

Airframe Noise Component Interaction Studies

Martin R. Fink, +1 more
- 01 Feb 1980 - 
- Vol. 17, Iss: 2, pp 99-105
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TLDR
In this article, an acoustic wind-tunnel test was conducted to examine the noise-generating processes of an airframe during approach flight, where high-lift leading and trailing edge devices and landing gear were added.
Abstract: 
Acoustic wind-tunnel tests were conducted to examine the noise-generating processes of an airframe during approach flight. The airframe model was a two-dimensional wing section, to which high-lift leading and trailing edge devices and landing gear were added. Far-field conventional microphones were utilized to determine component spectrum levels. An acoustic mirror directional microphone was utilized to examine differences in noise source distributions on airframe components extended separately and in combination. Measured spectra are compared with predictions inferred from aircraft flyover data. Aeroacoustic mechanisms for each airframe component are identified. Component interaction effects on total radiated noise generally were small (within about 2 dB). However, some interactions altered local flow velocities and turbulence levels, causing redistribution of local acoustic source strength. Possibilities for noise reduction exist if trailing edge flaps could be modified to decrease their noise radiation caused by incident turbulent flow.

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LOAN CCPY:--RET
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AFWL
TECHNICAL .‘t;:
KJRTLAND
AFB,
Interaction Studies
Martin R. Fink
and
Robert
H. Schiinker
CONTRACT NASI-15083
MARCH 1979
TECH LIBRARY KAFB, NY
NASA Contractor Report 3110
Airframe Noise Component
Interaction Studies
Martin R. Fink and Robert H. Schlinker
United Technologies Research Center
East Hartford, Conrrecticzct
Prepared for
Langley Research Center
under Contract NASl-15083
MSA
National Aeronautics
and Space Administration
Scientific and Technical
Information Office
1979
-
TABLE OF CONTENTS
Page
SUMMARY..
..
-.
............................
1
IN’lJRODUC TION
..............................
2
LISTOFSYMBOLS
.............................
3
DESCRIPTION OF EXPERIMENT
Acoustic Wind Tunnel. . . . . . . . . .
Instrumentation
Conventional Far-Field Microphones
Directional Microphone . . . . . .
Airframe Component Model
Clean Wing . . . . . . . . . . . .
Trailing Edge Flaps. . . . . . . .
Leading Edge Slat and Flap . . . .
Landing Gear . . . . . . . . . . .
Combined Configurations. . . . . .
Test Conditions and Procedures. . . . .
Wind Tunnel Corrections
Shear Layer Refraction Effects . .
Open Jet Effect on Angle of Attack
. . . . . . . . . . . . . .
4
..............
5
..............
5
..............
..............
i
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9
..............
9
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11
..............
11
. . . . . . . . . . . . . .
14
. . . . . . . . . . . . . .
17
COMPARISONS OF SINGLE-COMPONENT DATA AND PREDICTIONS
CleanWing
.............................
19
Leading Edge Flap
.........................
21
Leading Edge Slat
.........................
22
Landing Gear.
........................... 25
Trailing Edge Flaps
........................
28
Far Field Acoustic Spectra
..................
28
Surface Pressure Spectra
...................
30
Distribution of Noise Source Strength.
............
31
Directivity.
.........................
35
EVALUATION OF NOISE PROCESS FOR TRAILING EDGE FLAP
Analytical Concepts
........................
36
Turbulence Measurements
......................
37
Comparison of Calculated and Measured Spectra
...........
40
iii
Page
AIRFRAME COMPONENT NOISE INTERACTIONS
Leading Edge Devices and Landing Gear.
..............
41
Leading Edge Flap and Trailing Edge Flaps.
............
43
Leading Edge Slat and Trailing Edge Flaps.
............
45
Landing Gear and Trailing Edge Flaps
...............
47
Approach Configurations With Leading Edge Flaps.
......... 48
Approach Configurations With Leading Edge Slats.
......... 50
CONCLUSIONS ..............................
52
XZFEWCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
iv
Citations
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Proceedings ArticleDOI

Aircraft Optimization for Minimal Environmental Impact

Nicolas E. Antoine, +1 more
TL;DR: In this article, the authors investigate the trade-off between operating cost and environmental acceptability of commercial aircraft and determine the feasibility of including noise and emissions constraints in the early design of the aircraft and mission.
Journal ArticleDOI

Aircraft noise prediction

Antonio Filippone
- 01 Jul 2014 - 
TL;DR: It is contended that the field of aircraft noise prediction has not yet reached a sufficient level of maturity, in particular, some parametric effects cannot be investigated, issues of accuracy are not currently addressed, and validation standards are still lacking.
Journal ArticleDOI

Flap-edge aeroacoustic measurements and predictions

Thomas F. Brooks, +1 more
- 13 Mar 2003 - 
TL;DR: In this paper, a model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million.
Journal ArticleDOI

Reynolds-averaged Navier-Stokes computations of a flap-side-edge flowfield

Mehdi R. Khorrami, +2 more
- 01 Jan 1999 - 
TL;DR: In this paper, an extensive computational investigation of a generic high-lift configuration comprising a wing and a half-span flap reveals details of the mean flow field for flap deflections of 29 and 39 degrees.
Book

Aircraft optimization for minimal environmental impact

Nicolas E. Antoine, +1 more
TL;DR: In this paper, the authors investigate the trade-off between operating cost and environmental acceptability of commercial aircraft and determine the feasibility of including noise and emissions constraints in the early design of the aircraft and mission.
References
More filters
Journal ArticleDOI

Refraction of sound by a shear layer

R. K. Amiet
- 22 Jun 1978 - 
TL;DR: In this article, a comparison between several shear layer refraction theories is made to determine their relationship to one another and to determine which parameters are important for an open jet wind tunnel shear-layer correction.
Proceedings ArticleDOI

Correction of open jet wind tunnel measurements for shear layer refraction

R. K. Amiet
Proceedings ArticleDOI

Acoustic radiation and surface pressure characteristics of an airfoil due to incident turbulence

R. W. Paterson
TL;DR: In this paper, a theoretical and experimental investigation of the noise and unsteady surface pressure characteristics of an isolated airfoil in a uniform mean velocity, homogeneous, nearly-isotropic turbulence field was conducted.

Airframe Noise Prediction Method

Martin R. Fink
TL;DR: In this article, a noise component method is presented for calculating airframe noise, where the clean wing and tail surface noise is represented as a lift dipole normal to the deflected flap, with amplitude and spectrum given by a correlation of flyover data.

Atmospheric absorption of high frequency noise and application to fractional-octave bands

F. D. Shields, +1 more
TL;DR: In this paper, the authors measured pure tone sound absorption coefficients at 1/12 octave intervals from 4 to 100 KHz at 5.5K temperature intervals between 255.4 and 310.9 K and at 10 percent relative humidity increments between 0 percent and saturation in a large cylindrical tube (i.e., 25.4 cm; length, 4.8 m).