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Book Acoustical Evaluation of the NASA Lewis 9 by 15 Foot Low Speed Wind Tunnel

Download or read book Acoustical Evaluation of the NASA Lewis 9 by 15 Foot Low Speed Wind Tunnel written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-06 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The test section of the NASA Lewis 9- by 15-Foot Low Speed Wind Tunnel was acoustically treated to allow the measurement of acoustic sources located within the tunnel test section under simulated free field conditions. The treatment was designed for high sound absorption at frequencies above 250 Hz and to withstand tunnel airflow velocities up to 0.2 Mach. Evaluation tests with no tunnel airflow were conducted in the test section to assess the performance of the installed treatment. This performance would not be significantly affected by low speed airflow. Time delay spectrometry tests showed that interference ripples in the incident signal resulting from reflections occurring within the test section average from 1.7 dB to 3.2 dB wide over a 500 to 5150 Hz frequency range. Late reflections, from upstream and downstream of the test section, were found to be insignificant at the microphone measuring points. For acoustic sources with low directivity characteristics, decay with distance measurements in the test section showed that incident free field behavior can be measured on average with an accuracy of +/- 1.5 dB or better at source frequencies from 400 Hz to 10 kHz. The free field variations are typically much smaller with an omnidirectional source. Dahl, Milo D. and Woodward, Richard P. Glenn Research Center...

Book Comparison Between Design and Installed Acoustic Characteristics of NASA Lewis 9 by 15 Foot Low Speed Wind Tunnel Acoustic Treatment

Download or read book Comparison Between Design and Installed Acoustic Characteristics of NASA Lewis 9 by 15 Foot Low Speed Wind Tunnel Acoustic Treatment written by Milo D. Dahl and published by . This book was released on 1990 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book NASA Lewis 9 by 15 foot Low speed Wind Tunnel User Manual

Download or read book NASA Lewis 9 by 15 foot Low speed Wind Tunnel User Manual written by and published by . This book was released on 1993 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Acoustic Methods Used in the NASA Glenn 9 by 15 foot Low speed Wind Tunnel

Download or read book Acoustic Methods Used in the NASA Glenn 9 by 15 foot Low speed Wind Tunnel written by Clifford A. Brown and published by . This book was released on 2018 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Acoustic Performance of the Geae Ups Research Fan in the NASA Glenn 9 By 15 Foot Low Speed Wind Tunnel

Download or read book Acoustic Performance of the Geae Ups Research Fan in the NASA Glenn 9 By 15 Foot Low Speed Wind Tunnel written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-22 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: A model advanced turbofan was acoustically tested in the NASA Glenn 9- by 15-Foot Low-Speed Wind Tunnel in 1994. The Universal Propulsion Simulator fan was designed and manufactured by General Electric Aircraft Engines, and included an active core, as well as bypass, flow paths. The fan was tested with several rotors featuring unswept, forward-swept and aft-swept designs of both metal and composite construction. Sideline acoustic data were taken with both hard and acoustically treated walls in the flow passages. The fan was tested within an airflow at a Mach number of 0.20, which is representative of aircraft takeoff/approach conditions. All rotors showed similar aerodynamic performance. However, the composite rotors typically showed higher noise levels than did corresponding metal rotors. Aft and forward rotor sweep showed at most modest reductions of transonic multiple pure tone levels. However, rotor sweep often introduced increased rotor-stator interaction tone levels. Broadband noise was typically higher for the composite rotors and also for the aft-swept metal rotor. Transonic MPT generation was reduced with increasing fan axis angle of attack (AOA); however, higher downstream noise levels did increase with AOA resulting in higher overall Effective Perceived Noise Level. Woodward, Richard P. and Hughes, Christopher E. Glenn Research Center ACOUSTIC PROPERTIES; NOISE INTENSITY; AERODYNAMIC CHARACTERISTICS; MACH NUMBER; ANGLE OF ATTACK; AIR FLOW; WIND TUNNEL MODELS; WIND TUNNEL TESTS

Book NASA Lewis 9 By 15 Foot Low Speed Wind Tunnel User Manual

Download or read book NASA Lewis 9 By 15 Foot Low Speed Wind Tunnel User Manual written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-10 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: This manual describes the 9- by 15-Foot Low-Speed Wind Tunnel at the Lewis Research Center and provides information for users who wish to conduct experiments in this atmospheric facility. Tunnel variables such as pressures, temperatures, available tests section area, and Mach number ranges (0.05 to 0.20) are discussed. In addition, general support systems such as air systems, hydraulic system, hydrogen system, laser system, flow visualization system, and model support systems are described. Instrumentation and data processing and acquisition systems are also discussed. Soeder, Ronald H. Glenn Research Center...

Book Flowfield Measurements in the NASA Lewis Research Center 9 By 15 Foot Low Speed Wind Tunnel

Download or read book Flowfield Measurements in the NASA Lewis Research Center 9 By 15 Foot Low Speed Wind Tunnel written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-11-06 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: ational Aeronautics and Space Administration

Book Acoustic Performance of the Geae Ups Research Fan in the Nasa Glenn 9 by 15 Foot Low Speed Wind Tunnel

Download or read book Acoustic Performance of the Geae Ups Research Fan in the Nasa Glenn 9 by 15 Foot Low Speed Wind Tunnel written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-07 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: A model advanced turbofan was acoustically tested in the NASA Glenn 9- by 15-Foot Low-Speed Wind Tunnel in 1994. The Universal Propulsion Simulator fan was designed and manufactured by General Electric Aircraft Engines, and included an active core, as well as bypass, flow paths. The fan was tested with several rotors featuring unswept, forward-swept and aft-swept designs of both metal and composite construction. Sideline acoustic data were taken with both hard and acoustically treated walls in the flow passages. The fan was tested within an airflow at a Mach number of 0.20, which is representative of aircraft takeoff/approach conditions. All rotors showed similar aerodynamic performance. However, the composite rotors typically showed higher noise levels than did corresponding metal rotors. Aft and forward rotor sweep showed at most modest reductions of transonic multiple pure tone levels. However, rotor sweep often introduced increased rotor-stator interaction tone levels. Broadband noise was typically higher for the composite rotors and also for the aft-swept metal rotor. Transonic MPT generation was reduced with increasing fan axis angle of attack (AOA); however, higher downstream noise levels did increase with AOA resulting in higher overall Effective Perceived Noise Level.

Book Aeropropulsion Facilities at the NASA Lewis Research Center

Download or read book Aeropropulsion Facilities at the NASA Lewis Research Center written by Lewis Research Center and published by . This book was released on 1995 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: