Download or read book Experimental Verification of Propeller Noise Prediction written by G. P. Succi and published by . This book was released on 1980 with total page 13 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 . This book was released on 2018-11-13 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 Aeroacoustics of Flight Vehicles written by Harvey H. Hubbard and published by . This book was released on 1991 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Reference Publication written by and published by . This book was released on 1977 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low Noise Propeller Technology Demonstration written by Edward D. Griffith and published by . This book was released on 1973 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quiet aircraft used for covert aerial night reconnaissance employ low tip speed propellers to achieve a minimum acoustic noise signature. This study was initiated when certain unexpected and anomalous trends in the measured propeller noise of such aircraft were compared to predictions of noise made by the Air Force Propeller Noise Prediction Program. Large discrepancies in both trends and levels were noted between measured and predicted noise. Therefore, the goal of this study was the modification of an existing Air Force computer program such that accurate predictions of far field noise for low tip speed propellers can be made. Empirical data from previous quiet airplane experiments were used to develop modifications to both rotational and vortex noise prediction methods for propellers operating in the tip speed range from Mach 0.2 to 0.4.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1970 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book State of the art of High Speed Propeller Noise Prediction written by F. Farassat and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeroacoustics of Flight Vehicles written by Harvey H. Hubbard and published by . This book was released on 1991 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NOISE CON Proceedings written by Ilene J Busch-Vishniac and published by . This book was released on 1990 with total page 520 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 Donald B. Hanson and published by . This book was released on 1993 with total page 118 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 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Procedure for Noise Prediction and Optimization of Advanced Technology Propellers written by Wen-Huei Jou and published by . This book was released on 1979 with total page 60 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 Users Manual for the Langley High Speed Propeller Noise Prediction Program DFP ATP written by M. H. Dunn and published by . This book was released on 1989 with total page 52 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 1983 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Propeller Noise at Low Tip Speeds written by David Brown and published by . This book was released on 1971 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study comprises an analytical and experimental investigation of the vortex noise generated by low-tip speed propellers. Initally, the treatment of the subject is focussed on an examination of the origins of broadband noise and the methods by which these can be analytically represented. Subsequent noise measurements on simple-design propellers indicate how the typical spectra in the Strouhal frequency range are significantly influenced by an extensive range of high order harmonics of the blade passage frequency, and a treatment of this harmonic content is included in this study report. The broadband and harmonic components of noise data, obtained from propellers with blade number and blade angle variations, have been analyzed in detail and noise prediction methods have been derived for each. It is postulated that the noise source mechanisms may be associated with unstable laminar flow separation (or transition) at the blade surfaces. The report also includes a set of graphical procedures by which both harmonic and random spectral details of the radiated noise can be calculated by tip Mach numbers in the range 0.2 to 0.6. (Author).
Download or read book Experimental Investigation of Propeller Noise as Related to Aerodynamic Flow written by Hugh Lowell Hanson and published by . This book was released on 1941 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt:
