Download or read book Acoustic Treatment Design Scaling Methods Volume 5 Analytical and Experimental Data Correlation written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-27 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary purpose of the study presented in this volume is to present the results and data analysis of in-duct transmission loss measurements. Transmission loss testing was performed on full-scale, 1/2-scale, and 115-scale treatment panel samples. The objective of the study was to compare predicted and measured transmission loss for full-scale and subscale panels in an attempt to evaluate the variations in suppression between full- and subscale panels which were ostensibly of equivalent design. Generally, the results indicated an unsatisfactory agreement between measurement and prediction, even for full-scale. This was attributable to difficulties encountered in obtaining sufficiently accurate test results, even with extraordinary care in calibrating the instrumentation and performing the test. Test difficulties precluded the ability to make measurements at frequencies high enough to be representative of subscale liners. It is concluded that transmission loss measurements without ducts and data acquisition facilities specifically designed to operate with the precision and complexity required for high subscale frequency ranges are inadequate for evaluation of subscale treatment effects.Chien, W. E. and Kraft, R. E. and Syed, A. A.Glenn Research Center; Langley Research CenterAIRCRAFT NOISE; ACOUSTICS; FREQUENCY RANGES; DUCTS; NOISE REDUCTION; TRANSMISSION LOSS; CALIBRATING; DATA ACQUISITION; PANELS...
Download or read book Acoustic Treatment Design Scaling Methods written by and published by . This book was released on 1999 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustic Treatment Design Scaling Methods written by R. E. Kraft and published by . This book was released on 1999 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustic Treatment Design Scaling Methods Volume 1 Overview Results and Recommendations written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-15 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scale model fan rigs that simulate new generation ultra-high-bypass engines at about 1/5-scale are achieving increased importance as development vehicles for the design of low-noise aircraft engines. Testing at small scale allows the tests to be performed in existing anechoic wind tunnels, which provides an accurate simulation of the important effects of aircraft forward motion on the noise generation. The ability to design, build, and test miniaturized acoustic treatment panels on scale model fan rigs representative of the fullscale engine provides not only a cost-savings, but an opportunity to optimize the treatment by allowing tests of different designs. The primary objective of this study was to develop methods that will allow scale model fan rigs to be successfully used as acoustic treatment design tools. The study focuses on finding methods to extend the upper limit of the frequency range of impedance prediction models and acoustic impedance measurement methods for subscale treatment liner designs, and confirm the predictions by correlation with measured data. This phase of the program had as a goal doubling the upper limit of impedance measurement from 6 kHz to 12 kHz. The program utilizes combined analytical and experimental methods to achieve the objectives. Kraft, R. E. and Yu, J. Glenn Research Center; Langley Research Center NASA/CR-1999-209120/VOL1, NAS 1.26:209120/VOL1
Download or read book NASA Langley Scientific and Technical Information Output 1999 written by and published by . This book was released on 2000 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustic Treatment Design Scaling Methods written by and published by . This book was released on 1999 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 2000 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustic Treatment Design Scaling Methods Volume 3 Test Plans Hardware Results and Evaluation written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-27 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to design, build, and test miniaturized acoustic treatment panels on scale-model fan rigs representative of the full-scale engine provides not only a cost-savings, but an opportunity to optimize the treatment by allowing tests of different designs. To be able to use scale model treatment as a full-scale design tool, it is necessary that the designer be able to reliably translate the scale model design and performance to an equivalent full-scale design. The primary objective of the study presented in this volume of the final report was to conduct laboratory tests to evaluate liner acoustic properties and validate advanced treatment impedance models. These laboratory tests include DC flow resistance measurements, normal incidence impedance measurements, DC flow and impedance measurements in the presence of grazing flow, and in-duct liner attenuation as well as modal measurements. Test panels were fabricated at three different scale factors (i.e., full-scale, half-scale, and one-fifth scale) to support laboratory acoustic testing. The panel configurations include single-degree-of-freedom (SDOF) perforated sandwich panels, SDOF linear (wire mesh) liners, and double-degree-of-freedom (DDOF) linear acoustic panels.Yu, J. and Kwan, H. W. and Echternach, D. K. and Kraft, R. E. and Syed, A. A.Langley Research CenterAIRCRAFT NOISE; ACOUSTIC PROPERTIES; SCALE MODELS; COST REDUCTION; FLOW RESISTANCE; GRAZING FLOW; IMPEDANCE MEASUREMENT; WIRE CLOTH; SANDWICH STRUCTURES; MINIATURIZATION; DEGREES OF FREEDOM; DUCTS...
Download or read book ACOUSTIC TREATMENT DESIGN SCALING METHODS NASA CR 1999 209120 VOL 5 AUG 6 1999 written by and published by . This book was released on 1999* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 1028 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
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Download or read book NASA Technical Memorandum written by and published by . This book was released on 1978 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:
