NASA Technical Reports Server (NTRS) 20050198963: NASA's Vision for Jet Noise Engineering

2.9 MB·English

by  NASA Technical Reports Server (NTRS)

Abstract :
Until recently, the design of jet engines for quiet operation was
limited by engineers' ability to predict the jet noise generated by a
nozzle exhaust system. More importantly, the 'intermediate steps'
between nozzle design and noise had not been understood, limiting
the design process to small variations around existing solutions. In
recent years NASA's Quiet Aircraft Technology (QAT) Program
has advanced the understanding and modeling of jet noise to give
engineers the tools they need to design quiet nozzle systems for
subsonic exhaust systems. The presentation discusses the approach
followed for QAT and argues that a similar effort aimed at
supersonic jet exhaust systems will be needed to allow designs of
quiet military aircraft in the future.
NASA’s Vision for Jet Noise
t ng Ii neering
Dr. Kevin W. Kinzie Dr. James E. Bridges
Dr. Brenda S. Henderson NASA Glenn Research Center
NASA Langley Research Center
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Jet Noise Problem
Far-field Noise
ur understanding of th
noise generation proce
noise is caused
distributed turbulent
Shear Layer
Initial Conditions Tu rbu I e nce
Characteristics
A comprehensive understanding of jet flowfield is at
the heart of any jet noise reduction strategy
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Global Scaling Laws
Single most effective jet noise
reduction technique is to
reduce the jet velocity
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SPL 1Olog
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This level of knowledge will not allow us to design a
quiet aircraft
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