Download or read book A Comparison Between an Existing Propeller Noise Theory and Wind Tunnel Data written by and published by . This book was released on 1980 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Technical Paper written by and published by . This book was released on 1990 with total page 728 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 716 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Technical Paper written by United States. National Aeronautics and Space Administration and published by . This book was released on 1990 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Technical Memorandum written by and published by . This book was released on 1981 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Possible Explanation for the Present Difference Between Linear Noise Theory and Experimental Data for Supersonic Helical Tip Speed Propellers written by and published by . This book was released on 1983 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Shock and Vibration Digest written by and published by . This book was released on 1980 with total page 660 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Investigation of the Effect of Boundary Layer Refraction on the Noise from a High Speed Propeller written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-16 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Models of supersonic propellers were previously tested for acoustics in the Lewis 8- by 6-Foot Wind Tunnel using pressure transducers mounted in the tunnel ceiling. The boundary layer on the tunnel ceiling is believed to refract some of the propeller noise away from the measurement transducers. Measurements were made on a plate installed in the wind tunnel which had a thinner boundary layer than the ceiling boundary layer. The plate was installed in two locations for comparison with tunnel ceiling noise data and with fuselage data taken on the NASA Dryden Jetstar airplane. Analysis of the data indicates that the refraction increases with: increasing boundary layer thickness; increasing free stream Mach number; increasing frequency; and decreasing sound radiation angle (toward the inlet axis). At aft radiation angles greater than about 100 deg there was little or no refraction. Comparisons with the airplane data indicated that not only is the boundary layer thickness important but also the shape of the velocity profile. Comparisons with an existing two-dimensional theory, using an idealized shear layer to approximate the boundary layer, showed that the theory and data had the same trends. Analysis of the data taken in the tunnel at two different distances from the propeller indicates a decay with distance in the wind tunnel at high Mach numbers but the decay at low Mach numbers is not as clear. Dittmar, J. H. and Burns, R. J. and Leciejewski, D. J. Glenn Research Center NASA-TM-83764, E-2257, NAS 1.15:83764 RTOP 535-03-12...

Download or read book Further Comparison of Wind Tunnel and Airplane Acoustic Data for Advanced Design High Speed Propeller Models written by and published by . This book was released on 1985 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theory for Noise of Propellers in Angular Inflow with Parametric Studies and Experimental Verification written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-23 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the derivation of a frequency domain theory and working equations for radiation of propeller harmonic noise in the presence of angular inflow. In applying the acoustic analogy, integration over the tangential coordinate of the source region is performed numerically, permitting the equations to be solved without approximation for any degree of angular inflow. Inflow angle is specified in terms of yaw, pitch, and roll angles of the aircraft. Since these can be arbitrarily large, the analysis applies with equal accuracy to propellers and helicopter rotors. For thickness and loading, the derivation is given in complete detail with working equations for near and far field. However, the quadrupole derivation has been carried only far enough to show feasibility of the numerical approach. Explicit formulas are presented for computation of source elements, evaluation of Green's functions, and location of observer points in various visual and retarded coordinate systems. The resulting computer program, called WOBBLE has been written in FORTRAN and follows the notation of this report very closely. The new theory is explored to establish the effects of varying inflow angle on axial and circumferential directivity. Also, parametric studies were performed to evaluate various phenomena outside the capabilities of earlier theories, such as an unsteady thickness effect. Validity of the theory was established by comparison with test data from conventional propellers and Prop Fans in flight and in wind tunnels under a variety of operating conditions and inflow angles. Hanson, Donald B. and Parzych, David J. Unspecified Center AEROACOUSTICS; NOISE PREDICTION (AIRCRAFT); PROPELLER FANS; PROPELLER NOISE; ACOUSTIC FREQUENCIES; COMPUTER PROGRAMS; DIRECTIVITY; FAR FIELDS; GREEN'S FUNCTIONS; NEAR FIELDS; PROP-FAN TECHNOLOGY; PROPELLER BLADES; QUADRUPOLES...

Download or read book NASA Conference Publication written by and published by . This book was released on 1981 with total page 824 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Turboprop Project written by Roy D. Hager and published by . This book was released on 1988 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA SP written by and published by . This book was released on 1991 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aeronautical Engineering written by and published by . This book was released on 1991 with total page 1112 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).

Download or read book Additional Noise Data on the SR 3 Propeller written by James H. Dittmar and published by . This book was released on 1981 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 1980 Aircraft Safety and Operating Problems written by and published by . This book was released on 1981 with total page 820 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Annual Report of the National Advisory Committee for Aeronautics written by United States. National Advisory Committee for Aeronautics and published by . This book was released on 1950 with total page 988 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes the Committee's Technical reports no. 1-1058, reprinted in v. 1-37.