Journal ArticleDOI
Acoustic characteristics of two hybrid inlets at forward speed
M. D. Falarski,Michael T. Moore +1 more
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TLDR
In this paper, a wind tunnel investigation of the acoustic and aerodynamic characteristics of two hybrid inlets installed on a JT15D-1 turbofan engine was performed.Abstract:
A wind tunnel investigation of the acoustic and aerodynamic characteristics of two hybrid inlets installed on a JT15D-1 turbofan engine was performed. The hybrid inlets combined moderate throat Mach number and wall acoustic treatment to suppress the fan inlet noise. Acoustic and aerodynamic data were recorded over a range of flight and engine operating conditions. In a simulated flight environment, the hybrid inlets provided significant levels of suppression at both design and off-design throat Mach numbers with good aerodynamic performance. A comparison of inlet noise at quasi-static and forward-speed conditions in the wind tunnel showed a reduction in the fan tones, demonstrating the flight cleanup effect. High angles of attack produced slight increases in fan noise at the high acoustic directivity angles.read more
Citations
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Journal ArticleDOI
Flight Effects on Fan Noise with Static and Wind-Tunnel Comparisons
John S. Preisser,David Chestnutt +1 more
TL;DR: In this paper, a flight test program utilizing a JT15D-1 turbofan engine has been conducted with the objectives of studying flight effects on fan noise and evaluating the simulation effectiveness of both a wind tunnel and a static test configuration that incorporated an inlet control device (ICD).
Proceedings ArticleDOI
A Mode Detection Method Using the Azimuthal Directivity of a Turbofan Model
TL;DR: In this paper, the azimuthal, far field directivity of a scale fan model was measured in high resolution in an anechoic chamber with an inflow control device and a baffle separating the aft and forward radiated interaction noise.
Proceedings ArticleDOI
Unsteady fan blade pressure and acoustic radiation from a JT15D-1 turbofan engine at simulated forward speed
TL;DR: In this paper, the effects of varying engine rpm, changing the angle-of-attack of the engine inlet to tunnel flow and mounting an aircraft wing to simulate an installation condition on an actual aircraft are presented.
Proceedings ArticleDOI
Azimuthal Patterns of the Radiated Sound Field From a Turbofan Model
TL;DR: In this paper, the authors measured the azimuthal directivity of a scale fan model with 16 rotors and 40 stator vanes at a tip speed of 905 ft/sec in an anechoic chamber with an inflow control device installed on the stationary fan model.
Test-engine and inlet performance of an aircraft used for investigating flight effects on fan noise
R. A. Golub,J. S. Preisser +1 more
TL;DR: In this article, a Grumman OV-1B Mohawk aircraft was modified to carry a modified and instrumented Pratt & Whitney JT15D-1 turbofan engine.
References
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Journal ArticleDOI
The Cause of Tone Generation by Aero-Engine Fans at High Subsonic Tip Speeds and the Effect of Forward Speed
N. A. Cumpsty,B. W. Lowrie +1 more
Proceedings ArticleDOI
Effects of forward velocity and acoustic treatment on inlet fan noise
C. E. Feiler,J. E. Merriman +1 more
TL;DR: In this article, flyover and static noise data from several engines are presented that show inlet fan noise measured in flight can be lower than that projected from static tests for some engines.
Proceedings ArticleDOI
Model and full scale test results relating to fan noise in-flight effects
J. Roundhill,L. Schaut +1 more
Further studies of static to flight effects on fan tone noise using inlet distortion control for source identification
TL;DR: In this article, the effect of atmospheric turbulence on tone-noise generation was investigated using a distortion control inlet with a modern day turbofan engine to assess atmospheric turbulence effects.