Predictions of Supersonic Jet Mixing and Shock-Associated Noise Compared with Measured Far-Field Data PDF Download
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Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781719493345
Category :
Languages : en
Pages : 78
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Book Description
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
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781719493345
Category :
Languages : en
Pages : 78
Get Book Here
Book Description
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
Author: Milo D. Dahl
Publisher:
ISBN:
Category :
Languages : en
Pages : 74
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Book Description
Author: Nasa Technical Reports Server (Ntrs)
Publisher: BiblioGov
ISBN: 9781289236328
Category :
Languages : en
Pages : 84
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Book Description
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.
Author:
Publisher:
ISBN:
Category : Jet planes
Languages : en
Pages : 176
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 12
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Book Description
Author:
Publisher:
ISBN:
Category : Jet planes
Languages : en
Pages : 50
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Book Description
Author: J. B. Ollerhead
Publisher:
ISBN:
Category : Noise
Languages : en
Pages : 116
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Book Description
Author: Milo D. Dahl
Publisher:
ISBN:
Category :
Languages : en
Pages : 16
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Book Description
Author: H. K. Tanna
Publisher:
ISBN:
Category : Jet planes
Languages : en
Pages : 0
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Book Description
The characteristics, both spectral and directivity, of the sound field of supersonic shock-free jets are studied by measuring the turbulent mixing noise in the far field from four two-inch diameter nozzles, namely a convergent nozzle for pressure ratios up to critical and three convergent- divergent nozzles having nominal design Mach numbers of 1.4, 1.7, and 2.0, respectively. The measurements were conducted in a free-field environment. The results from 75 jet exit conditions are presented in a systematic manner in the form of tabulated one-third octave spectra. The test program was carefully planned in order to obtain results (i) at constant jet efflux temperature with varying jet velocity, and conversely (ii) at constant exit velocity while varying jet efflux temperature. The effects of jet velocity and exhaust temperature on turbulent mixing noise can therefore be assessed independently.
Author: Andrew Thomas Merck
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
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.
