Transonic Rotor Noise Theoretical And Experimental Comparisons

Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 32 pages
File Size : 55,9 Mb
Release : 2018-08-06
Category : Electronic
ISBN : 1724753509

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Transonic Rotor Noise by National Aeronautics and Space Administration (NASA) Pdf

Two complementary methods of describing the high speed rotor noise problem are discussed. The first method uses the second order transonic potential equation to define and characterize the nature of the aerodynamic and acoustic fields and to explain the appearance of radiating shock waves. The second employs the Ffowcs Williams and Hawkings equation to successfully calculate the acoustic far field. Good agreement between theoretical and experimental waveforms is shown for transonic hover tip Mach numbers from 0.8 to 0.9. Schmitz, F. H. and Yu, Y. H. Ames Research Center NASA-TM-81236, A-8342, AVRADCOM-TR-80-A-12 RTOP 992-21-01-90-01

Author : Anonim
Publisher : Unknown
Page : 42 pages
File Size : 43,6 Mb
Release : 1980
Category : Electronic
ISBN : NASA:31769000547524

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Transonic Rotor Noise: Theoretical and Experimental Comparisons by Anonim Pdf

Two complementary methods of describing the high-speed rotor noise problem are discussed. The first method uses the second-order transonic potential equation to define and characterize the nature of the aerodynamic and acoustic fields and to explain the appearance of radiating shock waves. The second employs the Ffowcs Williams and Hawkings equation to successfully calculate the acoustic far-field. Good agreement between theoretical and experimental waveforms is shown for transonic hover tip Mach numbers from 0.8 to 0.9. (Author).

Author : F. H. Schmitz
Publisher : Unknown
Page : 110 pages
File Size : 51,8 Mb
Release : 1983
Category : Electronic
ISBN : NASA:31769000557143

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Helicopter Impulsive Noise: Theoretical and Experimental Status by F. H. Schmitz Pdf

The theoretical and experimental status of helicopter impulsive noise is reviewed. The two major source mechanisms of helicopter impulsive noise are addressed: high-speed impulsive noise and blade-vortex interaction impulsive noise. A thorough physical explanation of both generating mechanisms is presented together with model and full-scale measurements of the phenomena. Current theoretical prediction methods are compared with experimental findings of isolated rotor tests. The noise generating mechanisms of high speed impulsive noise are fairly well understood - theory and experiment compare nicely over Mach number ranges typical of today's helicopters. For the case of blade-vortex interaction noise, understanding of noise generating mechanisms and theoretical comparison with experiment are less satisfactory. Several methods for improving theory-experiment are suggested.

Author : Harvey H. Hubbard
Publisher : Unknown
Page : 616 pages
File Size : 40,8 Mb
Release : 1991
Category : Aerodynamic noise
ISBN : UCAL:B5262564

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Aeroacoustics of Flight Vehicles by Harvey H. Hubbard Pdf

Author : Anonim
Publisher : Unknown
Page : 628 pages
File Size : 50,7 Mb
Release : 1977
Category : Astronautics
ISBN : MINN:31951P001419031

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NASA Reference Publication by Anonim Pdf

Author : A. Krothapalli,C.A. Smith
Publisher : Springer Science & Business Media
Page : 511 pages
File Size : 47,6 Mb
Release : 2012-12-06
Category : Science
ISBN : 9781461248408

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Recent Advances in Aeroacoustics by A. Krothapalli,C.A. Smith Pdf

The Joint Institute for Aeronautics and Acoustics at Stanford University was established in October 1973 to provide an academic environment for long-term cooperative research between Stanford and NASA Ames Research Center. Since its establishment, the Institute has conducted theoretical and experimental work in the areas of aerodynamics, acoustics, fluid mechanics, flight dynamics, guidance and control, and human factors. This research has involved Stanford faculty, research associates, graduate students, and many distinguished visitors in collaborative efforts with the research staff of NASA Ames Research Center. The occasion of the Institute's tenth anniversary was used to reflect back on where that research has brought us, and to consider where our endeavors should be directed next. Thus, an International Symposium was held to review recent advances in the fields relevant to the activities of the Institute and to discuss the areas of research to be undertaken in the future. This anniversary was also chosen as an opportunity to honor one of the Institute's founders and its director, Professor Krishnamurty Karamcheti. It has been his crea tive inspiration that has provided the ideal research environment at the Joint Institute.

Author : Anonim
Publisher : Unknown
Page : 704 pages
File Size : 47,9 Mb
Release : 1995
Category : Aeronautics
ISBN : UIUC:30112050127304

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Scientific and Technical Aerospace Reports by Anonim Pdf

Author : Anonim
Publisher : Unknown
Page : 620 pages
File Size : 51,8 Mb
Release : 1974
Category : Mechanics, Applied
ISBN : UCAL:C2682447

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Applied Mechanics Reviews by Anonim Pdf

Author : Anonim
Publisher : Unknown
Page : 616 pages
File Size : 52,8 Mb
Release : 1991
Category : Electronic
ISBN : NASA:31769000527179

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Aeroacoustics of Flight Vehicles: Theory and Practice. Volume 1: Noise Sources by Anonim Pdf

The field of aeroacoustics has matured dramatically in the past two decades. Researchers have gained significant theoretical and experimental understanding of the noise generated by aircraft power plants and their components. In addition, airframe noise and interior noise have been investigated extensively. The physical understanding obtained from these efforts has resulted in the development of hardware capable of reducing community noise and of meeting strict noise certification requirements. Reductions in overall sound pressure level of 20 to 30 dB have been obtained for some types of power plants, while in the same period their installed power has increased significantly. Current quiet flight vehicle designs are based on information reported in a multitude of journals, conference proceeding, research reports, and specialized books. Each of these scientific publications represents only incremental steps in the evolution of our present understanding of the various aeroacoustic noise generation and propagation mechanisms and procedures for noise control.

Author : Anonim
Publisher : Unknown
Page : 806 pages
File Size : 46,6 Mb
Release : 1987
Category : Helicopters
ISBN : UOM:39015016523501

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Vertica by Anonim Pdf

Author : Harvey H. Hubbard
Publisher : Unknown
Page : 612 pages
File Size : 48,8 Mb
Release : 1991
Category : Airplanes
ISBN : UCBK:C076923342

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Aeroacoustics of Flight Vehicles: Noise sources by Harvey H. Hubbard Pdf

Author : Anonim
Publisher : Unknown
Page : 654 pages
File Size : 42,5 Mb
Release : 1986
Category : Aerodynamic noise
ISBN : PSU:000009834453

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AIAA 86-1900 - AIAA 86-1994 (with omissions in numbering) by Anonim Pdf

Author : American Helicopter Society
Publisher : Unknown
Page : 710 pages
File Size : 43,5 Mb
Release : 1998
Category : Helicopters
ISBN : UOM:39015048207917

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Journal of the American Helicopter Society by American Helicopter Society Pdf

Author : Anonim
Publisher : Unknown
Page : 204 pages
File Size : 43,6 Mb
Release : 1980
Category : Science
ISBN : CORNELL:31924057177820

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Technical Abstract Bulletin by Anonim Pdf

Author : Anonim
Publisher : Unknown
Page : 282 pages
File Size : 43,7 Mb
Release : 1987
Category : Aerodynamic noise
ISBN : PSU:000013473068

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AIAA 11th Aeroacoustics Conference by Anonim Pdf