Author: Terrill W. Putnam
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 38
Book Description
Measurements of engine noise generated by an F-111A airplane positioned on a thrustmeasuring platform were made at angles of 0 deg to 160 deg from the aircraft heading. Sound power levels, power spectra, and directivity patterns are presented for jet exit velocities between 260 feet per second and 2400 feet per second. The test results indicate that the total acoustic power was proportional to the eighth power of the core jet velocity for core exhaust velocities greater than 300 meters per second (985 feet per second) and that little or no mixing of the core and fan streams occurred. The maximum sideline noise was most accurately predicted by using the average jet velocity for velocities above 300 meters per second (985 feet per second). The acoustic power spectrum was essentially the same for the single jet flow of afterburner operation and the coaxial flow of the nonafterburning condition. By varying the inlet geometry and cowl position, reductions in the sound pressure level of the blade passing frequency on the order of 15 decibels to 25 decibels were observed for inlet Mach numbers of 0.8 to 0.9.
Investigation of Coaxial Jet Noise and Inlet Choking Using an F-111A Airplane
Author: Terrill W. Putnam
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 38
Book Description
Measurements of engine noise generated by an F-111A airplane positioned on a thrustmeasuring platform were made at angles of 0 deg to 160 deg from the aircraft heading. Sound power levels, power spectra, and directivity patterns are presented for jet exit velocities between 260 feet per second and 2400 feet per second. The test results indicate that the total acoustic power was proportional to the eighth power of the core jet velocity for core exhaust velocities greater than 300 meters per second (985 feet per second) and that little or no mixing of the core and fan streams occurred. The maximum sideline noise was most accurately predicted by using the average jet velocity for velocities above 300 meters per second (985 feet per second). The acoustic power spectrum was essentially the same for the single jet flow of afterburner operation and the coaxial flow of the nonafterburning condition. By varying the inlet geometry and cowl position, reductions in the sound pressure level of the blade passing frequency on the order of 15 decibels to 25 decibels were observed for inlet Mach numbers of 0.8 to 0.9.
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 38
Book Description
Measurements of engine noise generated by an F-111A airplane positioned on a thrustmeasuring platform were made at angles of 0 deg to 160 deg from the aircraft heading. Sound power levels, power spectra, and directivity patterns are presented for jet exit velocities between 260 feet per second and 2400 feet per second. The test results indicate that the total acoustic power was proportional to the eighth power of the core jet velocity for core exhaust velocities greater than 300 meters per second (985 feet per second) and that little or no mixing of the core and fan streams occurred. The maximum sideline noise was most accurately predicted by using the average jet velocity for velocities above 300 meters per second (985 feet per second). The acoustic power spectrum was essentially the same for the single jet flow of afterburner operation and the coaxial flow of the nonafterburning condition. By varying the inlet geometry and cowl position, reductions in the sound pressure level of the blade passing frequency on the order of 15 decibels to 25 decibels were observed for inlet Mach numbers of 0.8 to 0.9.
NASA Technical Note
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 450
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 450
Book Description
NASA Technical Memorandum
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 388
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 388
Book Description
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1280
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1280
Book Description
The Shock and Vibration Digest
Author:
Publisher:
ISBN:
Category : Shock (Mechanics)
Languages : en
Pages : 488
Book Description
Publisher:
ISBN:
Category : Shock (Mechanics)
Languages : en
Pages : 488
Book Description
Applied Mechanics Reviews
Author:
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 628
Book Description
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 628
Book Description
Annual Meeting, Society of Engineering Science
Author: Society of Engineering Science
Publisher:
ISBN:
Category : Engineering
Languages : en
Pages : 484
Book Description
Publisher:
ISBN:
Category : Engineering
Languages : en
Pages : 484
Book Description
Monthly Catalog, United States Public Documents
Author: United States. Superintendent of Documents
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1252
Book Description
February issue includes Appendix entitled Directory of United States Government periodicals and subscription publications; September issue includes List of depository libraries; June and December issues include semiannual index.
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1252
Book Description
February issue includes Appendix entitled Directory of United States Government periodicals and subscription publications; September issue includes List of depository libraries; June and December issues include semiannual index.
Monthly Catalog of United States Government Publications
Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1386
Book Description
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1386
Book Description
Monthly Catalog of United States Government Publications, Cumulative Index
Author: United States. Superintendent of Documents
Publisher:
ISBN:
Category : United States
Languages : en
Pages : 1466
Book Description
Publisher:
ISBN:
Category : United States
Languages : en
Pages : 1466
Book Description