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RANS Analyses of Turbofan Nozzles with Wedge Deflectors for Noise ReductionComputational fluid dynamics (CFD) was used to evaluate a promising concept for reducing the noise at take-off of dual-stream, turbofan nozzles. The concept, offset stream technology, reduces the jet noise observed on the ground by diverting (offsetting) the majority of the fan flow below the core flow, thickening this layer between the high velocity core flow and the ground observers. In this study a wedge placed in the internal fan stream is used as the diverter. Wind, a Reynolds Averaged Navier-Stokes (RANS) code, was used to analyze the flowfield of the exhaust plume and to calculate nozzle performance. Results showed that the wedge effectively diverts the fan flow and the turbulent kinetic energy on the observer side of the nozzle is reduced. The reduction in turbulent kinetic energy should correspond to a reduction in noise. The blockage due to the wedge reduces the fan massflow proportional to its blockage and the overall thrust is consequently reduced. The CFD predictions are in very good agreement with experimental data. This noise reduction concept shows promise for reduced jet noise at a small reduction in thrust. It has been demonstrated that RANS CFD can be used to optimize this concept.
Document ID
20080005528
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
DeBonis, James R. (NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 24, 2013
Publication Date
January 7, 2008
Subject Category
Aerodynamics
Meeting Information
Meeting: 46th AIAA Aerospace Sciences Meeting
Location: Reno, NV
Country: United States
Start Date: January 7, 2008
End Date: January 10, 2008
Sponsors: American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 984754.02.07.03.13.05
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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