Broadband Noise Of Fans With Unsteady Coupling Theory To Account For Rotor And Stator Reflection
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Broadband Noise Of Fans With Unsteady Coupling Theory To Account For Rotor And Stator Reflection
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Author : United States. National Aeronautics and Space Administration
language : en
Publisher:
Release Date : 2002*
Broadband Noise Of Fans With Unsteady Coupling Theory To Account For Rotor And Stator Reflection written by United States. National Aeronautics and Space Administration and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002* with categories.
Broadband Noise Of Fans With Unsteady Coupling Theory To Account For Rotor And Stator Reflection Transmission Effects
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Author : National Aeronautics and Space Administration (NASA)
language : en
Publisher: Createspace Independent Publishing Platform
Release Date : 2018-05-29
Broadband Noise Of Fans With Unsteady Coupling Theory To Account For Rotor And Stator Reflection Transmission Effects written by National Aeronautics and Space Administration (NASA) and has been published by Createspace Independent Publishing Platform this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-05-29 with categories.
This report examines the effects on broadband noise generation of unsteady coupling between a rotor and stator in the fan stage of a turbofan engine. Whereas previous acoustic analyses treated the blade rows as isolated cascades, the present work accounts for reflection and transmission effects at both blade rows by tracking the mode and frequency scattering of pressure and vortical waves. The fan stage is modeled in rectilinear geometry to take advantage of a previously existing unsteady cascade theory for 3D perturbation waves and thereby use a realistic 3D turbulence spectrum. In the analysis, it was found that the set of participating modes divides itself naturally into "independent mode subsets" that couple only among themselves and not to the other such subsets. This principle is the basis for the analysis and considerably reduces computational effort. It also provides a simple, accurate scheme for modal averaging for further efficiency. Computed results for a coupled fan stage are compared with calculations for isolated blade rows. It is found that coupling increases downstream noise by 2 to 4 dB. Upstream noise is lower for isolated cascades and is further reduced by including coupling effects. In comparison with test data, the increase in the upstream/downstream differential indicates that broadband noise from turbulent inflow at the stator dominates downstream noise but is not a significant contributor to upstream noise.Hanson, Donald B.Glenn Research CenterTURBOFAN ENGINES; ENGINE NOISE; ROTOR STATOR INTERACTIONS; NOISE MEASUREMENT; TURBULENT FLOW; SIGNAL ANALYZERS; ACOUSTIC COUPLING; SOUND TRANSMISSION; WAVE REFLECTION; BROADBAND
Broadband Noise Of Fans
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Author : Donald B. Hanson
language : en
Publisher: BiblioGov
Release Date : 2013-08
Broadband Noise Of Fans written by Donald B. Hanson and has been published by BiblioGov this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-08 with categories.
This report examines the effects on broadband noise generation of unsteady coupling between a rotor and stator in the fan stage of a turbofan engine. Whereas previous acoustic analyses treated the blade rows as isolated cascades, the present work accounts for reflection and transmission effects at both blade rows by tracking the mode and frequency scattering of pressure and vortical waves. The fan stage is modeled in rectilinear geometry to take advantage of a previously existing unsteady cascade theory for 3D perturbation waves and thereby use a realistic 3D turbulence spectrum. In the analysis, it was found that the set of participating modes divides itself naturally into "independent mode subsets" that couple only among themselves and not to the other such subsets. This principle is the basis for the analysis and considerably reduces computational effort. It also provides a simple, accurate scheme for modal averaging for further efficiency. Computed results for a coupled fan stage are compared with calculations for isolated blade rows. It is found that coupling increases downstream noise by 2 to 4 dB. Upstream noise is lower for isolated cascades and is further reduced by including coupling effects. In comparison with test data, the increase in the upstream/downstream differential indicates that broadband noise from turbulent inflow at the stator dominates downstream noise but is not a significant contributor to upstream noise.
Monthly Catalog Of United States Government Publications
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Author :
language : en
Publisher:
Release Date : 2004-08
Monthly Catalog Of United States Government Publications written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004-08 with Government publications categories.
International Aerospace Abstracts
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Author :
language : en
Publisher:
Release Date : 1998
International Aerospace Abstracts written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Aeronautics categories.
Aerospace America
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Author :
language : en
Publisher:
Release Date : 1997
Aerospace America written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997 with Aeronautics categories.
Nasa Sp
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Author :
language : en
Publisher:
Release Date : 1992
Nasa Sp written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1992 with Aeronautics categories.
Aeronautical Engineering
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Author :
language : en
Publisher:
Release Date : 1992
Aeronautical Engineering written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1992 with Aeronautics categories.
A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).
A Cumulative Index To A Continuing Bibliography On Aeronautical Engineering
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Author :
language : en
Publisher:
Release Date : 1986
A Cumulative Index To A Continuing Bibliography On Aeronautical Engineering written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1986 with categories.
Government Reports Announcements Index
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Author :
language : en
Publisher:
Release Date : 1980-06
Government Reports Announcements Index written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1980-06 with Science categories.