Download or read book Supersonic Coaxial Jets Noise Predictions and Measurements written by and published by . This book was released on 1998 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book SUPERSONIC COAXIAL JETS NOISE PREDICTIONS AND MEASUREMENTS NASA TM 1998 207422 JUL 6 1998 written by United States. National Aeronautics and Space Administration and published by . This book was released on 1998* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Supersonic Coaxial Jet Noise Predictions written by Milo D. Dahl and published by . This book was released on 1995 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Aeroacoustics of Supersonic Coaxial Jets 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 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Instability waves have been established as the dominant source of mixing noise radiating into the downstream arc of a supersonic jet when the waves have phase velocities that are supersonic relative to ambient conditions. Recent theories for supersonic jet noise have used the concepts of growing and decaying linear instability waves for predicting radiated noise. This analysis is extended to the prediction of noise radiation from supersonic coaxial jets. Since the analysis requires a known mean flow and the coaxial jet mean flow is not described easily in terms of analytic functions, a numerical prediction is made for its development. The Reynolds averaged, compressible, boundary layer equations are solved using a mixing length turbulence model. Empirical correlations are developed for the effects of velocity and temperature ratios and Mach number. Both normal and inverted velocity profile coaxial jets are considered. Comparisons with measurements for both single and coaxial jets show good agreement. The results from mean flow and stability calculations are used to predict the noise radiation from coaxial jets with different operating conditions. Comparisons are made between different coaxial jets and a single equivalent jet with the same total thrust, mass flow, and exit area. Results indicate that normal velocity profile jets can have noise reductions compared to the single equivalent jet. No noise reductions are found for inverted velocity profile jets operated at the minimum noise condition compared to the single equivalent jet. However, it is inferred that changes in area ratio may provide noise reduction benefits for inverted velocity profile jets. Dahl, Milo D. Glenn Research Center AEROACOUSTICS; COAXIAL FLOW; GAS JETS; JET AIRCRAFT NOISE; NOISE PREDICTION (AIRCRAFT); NOISE REDUCTION; SUPERSONIC JET FLOW; COMPUTATIONAL FLUID DYNAMICS; FLOW STABILITY; MACH NUMBER; MIXING LENGTH FLOW THEORY; TEMPERATURE RATIO; VELOCITY DISTRIBUTION...
Download or read book The Development of a Fast Method for the Calculation of Noise from Supersonic Jets written by Andrew Thomas Merck and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of a high-speed jet noise prediction method that is significantly less computationally expensive than previous computationally-based methods and which provides a simple user interface is described. Several sets of far-field spectral density experimental data are decomposed into their large-scale turbulence component and the corresponding near-field wavenumber spectra are calculated. A wavepacket model is used to characterize the near-field wavenumber spectrum at the surface of the jet flow, and the wavepacket properties given by the near-field spectra at various frequencies and operating conditions are found using Gaussian fits. A large database is compiled from the wavepacket properties for a range of operating conditions, and the far-field jet noise is predicted using a mathematical model that combines the wavepacket model and existing models. Comparison of the wavepacket-model far-field supersonic jet noise predictions and experimental measurements are made, and the results demonstrate that the wavepacket-model results in accurate noise predictions.
Download or read book Predictions of Supersonic Jet Mixing and Shock Associated Noise Compared with Measured Far Field Data written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-07 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Codes for predicting supersonic jet mixing and broadband shock-associated noise were assessed using a database containing noise measurements of a jet issuing from a convergent nozzle. Two types of codes were used to make predictions. Fast running codes containing empirical models were used to compute both the mixing noise component and the shock-associated noise component of the jet noise spectrum. One Reynolds-averaged, Navier-Stokes-based code was used to compute only the shock-associated noise. To enable the comparisons of the predicted component spectra with data, the measured total jet noise spectra were separated into mixing noise and shock-associated noise components. Comparisons were made for 1/3-octave spectra and some power spectral densities using data from jets operating at 24 conditions covering essentially 6 fully expanded Mach numbers with 4 total temperature ratios.
Download or read book Predictions of Supersonic Jet Mixing and Shock Associated Noise Compared with Measured Far Field Data 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 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: Codes for predicting supersonic jet mixing and broadband shock-associated noise were assessed using a database containing noise measurements of a jet issuing from a convergent nozzle. Two types of codes were used to make predictions. Fast running codes containing empirical models were used to compute both the mixing noise component and the shock-associated noise component of the jet noise spectrum. One Reynolds-averaged, Navier-Stokes-based code was used to compute only the shock-associated noise. To enable the comparisons of the predicted component spectra with data, the measured total jet noise spectra were separated into mixing noise and shock-associated noise components. Comparisons were made for 1/3-octave spectra and some power spectral densities using data from jets operating at 24 conditions covering essentially 6 fully expanded Mach numbers with 4 total temperature ratios. Dahl, Milo D. Glenn Research Center JET MIXING FLOW; JET AIRCRAFT NOISE; SUPERSONIC JET FLOW; AERODYNAMIC NOISE; NOISE MEASUREMENT; NOISE SPECTRA; FLUID JETS; MACH NUMBER; PREDICTIONS; SHOCK WAVES; TEMPERATURE RATIO
Download or read book The Aeroacoustics of Supersonic Coaxial Jets written by Milo D. Dahl and published by . This book was released on 1994 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Prediction of the Near Field Noise of Supersonic Jets written by J. B. Ollerhead and published by . This book was released on 1967 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Generation and Radiation of Supersonic Jet Noise Append 2 Shock associated noise data written by and published by . This book was released on 1972 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Generation and Radiation of Supersonic Jet Noise Summary of supersonic jet noise studies written by and published by . This book was released on 1972 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Supersonic Jet Noise Reductions Predicted with Increased Jet Spreading Rate written by and published by . This book was released on 1995 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predictions of Supersonic Jet Mixing and Shock associated Noise Compared with Measured Far field Data written by Milo D. Dahl and published by . This book was released on 2010 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparison of Measured and Predicted Flight Effects on High bypass Coaxial Jet Exhaust Noise written by and published by . This book was released on 1983 with total page 24 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 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Noise Radiation by Instability Waves in Coaxial Jets written by Milo D. Dahl and published by . This book was released on 1994 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computation of Supersonic Jet Noise Under Imperfectly Expanded Conditions written by Chan M. Kim and published by . This book was released on 1993 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
