### Abstract

Recent theories for supersonic jet noise have used an instability wave noise generation model to predict radiated noise. This model requires a known mean flow that has typically been described by simple analytic functions for single jet mean flows. The mean flow of supersonic coaxial jets is not described easily in terms of analytic functions. To provide these profiles at all axial locations, a numerical scheme is developed to calculate the mean flow properties of a coaxial jet. The Reynolds-averaged, compressible, parabolic boundary layer equations are solved using a mixing length turbulence model. Empirical correlations are developed to account for the effects of velocity and temperature ratios and Mach number on the shear layer spreading. Both normal velocity profile and inverted velocity profile coaxial jets are considered. The mixing length model is modified in each case to obtain reasonable results when the two stream jet merges into a single fully developed jet. The mean flow calculations show both good qualitative and quantitative agreement with measurements in single and coaxial jet flows.

Original language | English (US) |
---|---|

Pages (from-to) | 643-663 |

Number of pages | 21 |

Journal | Journal of Sound and Vibration |

Volume | 200 |

Issue number | 5 |

DOIs | |

State | Published - Mar 13 1997 |

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### All Science Journal Classification (ASJC) codes

- Condensed Matter Physics
- Acoustics and Ultrasonics
- Mechanics of Materials
- Mechanical Engineering

### Cite this

*Journal of Sound and Vibration*,

*200*(5), 643-663. https://doi.org/10.1006/jsvi.1996.0723

}

*Journal of Sound and Vibration*, vol. 200, no. 5, pp. 643-663. https://doi.org/10.1006/jsvi.1996.0723

**Noise from supersonic coaxial jets, part 1 : Mean flow predictions.** / Dahl, M. D.; Morris, Philip John.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Noise from supersonic coaxial jets, part 1

T2 - Mean flow predictions

AU - Dahl, M. D.

AU - Morris, Philip John

PY - 1997/3/13

Y1 - 1997/3/13

N2 - Recent theories for supersonic jet noise have used an instability wave noise generation model to predict radiated noise. This model requires a known mean flow that has typically been described by simple analytic functions for single jet mean flows. The mean flow of supersonic coaxial jets is not described easily in terms of analytic functions. To provide these profiles at all axial locations, a numerical scheme is developed to calculate the mean flow properties of a coaxial jet. The Reynolds-averaged, compressible, parabolic boundary layer equations are solved using a mixing length turbulence model. Empirical correlations are developed to account for the effects of velocity and temperature ratios and Mach number on the shear layer spreading. Both normal velocity profile and inverted velocity profile coaxial jets are considered. The mixing length model is modified in each case to obtain reasonable results when the two stream jet merges into a single fully developed jet. The mean flow calculations show both good qualitative and quantitative agreement with measurements in single and coaxial jet flows.

AB - Recent theories for supersonic jet noise have used an instability wave noise generation model to predict radiated noise. This model requires a known mean flow that has typically been described by simple analytic functions for single jet mean flows. The mean flow of supersonic coaxial jets is not described easily in terms of analytic functions. To provide these profiles at all axial locations, a numerical scheme is developed to calculate the mean flow properties of a coaxial jet. The Reynolds-averaged, compressible, parabolic boundary layer equations are solved using a mixing length turbulence model. Empirical correlations are developed to account for the effects of velocity and temperature ratios and Mach number on the shear layer spreading. Both normal velocity profile and inverted velocity profile coaxial jets are considered. The mixing length model is modified in each case to obtain reasonable results when the two stream jet merges into a single fully developed jet. The mean flow calculations show both good qualitative and quantitative agreement with measurements in single and coaxial jet flows.

UR - http://www.scopus.com/inward/record.url?scp=0031099425&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031099425&partnerID=8YFLogxK

U2 - 10.1006/jsvi.1996.0723

DO - 10.1006/jsvi.1996.0723

M3 - Article

VL - 200

SP - 643

EP - 663

JO - Journal of Sound and Vibration

JF - Journal of Sound and Vibration

SN - 0022-460X

IS - 5

ER -