### Abstract

Language | English |
---|---|

Title of host publication | Studying Turbulence using Numerical Simulation Databases - XVI |

Subtitle of host publication | Proceedings of the 2016 Summer Program |

Place of Publication | Stanford, California |

Number of pages | 10 |

Publication status | Published - 31 Dec 2016 |

### Fingerprint

### Keywords

- jet noise predictions
- Gold-stein’s generalized acoustic analogy formulation
- adjoint vector Green’s function
- asymptotic approach
- turbulence
- mean flow

### Cite this

*Studying Turbulence using Numerical Simulation Databases - XVI: Proceedings of the 2016 Summer Program*Stanford, California.

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*Studying Turbulence using Numerical Simulation Databases - XVI: Proceedings of the 2016 Summer Program.*Stanford, California.

**Prediction of supersonic jet noise using non-parallel ﬂow asymptotics and LES data within Goldstein’s acoustic analogy.** / Afsar, M. Z.; Sescu, A.; Sassanis, V.; Towne, A.; Brès, G. A.; Lele, S. K.

Research output: Chapter in Book/Report/Conference proceeding › Chapter

TY - CHAP

T1 - Prediction of supersonic jet noise using non-parallel ﬂow asymptotics and LES data within Goldstein’s acoustic analogy

AU - Afsar, M. Z.

AU - Sescu, A.

AU - Sassanis, V.

AU - Towne, A.

AU - Brès, G. A.

AU - Lele, S. K.

PY - 2016/12/31

Y1 - 2016/12/31

N2 - In this study we show how accurate jet noise predictions can be achieved within Gold-stein’s generalized acoustic analogy formulation for heated and un-heated supersonic jets using a previously developed asymptotic theory for the adjoint vector Green’s function. In this approach, mean ﬂow non-parallelism enters the leading order dominant balance producing enhanced ampliﬁcation at low frequencies, which we believe corresponds to the peak sound at small polar observation angles. We determine all relevant mean ﬂow and turbulence quantities using Large Eddy Simulations of two axi-symmetric round jets at ﬁxed jet Mach number and diﬀerent nozzle temperature ratios. Certain empirical co-eﬃcients that enter the turbulence length scales formula are tuned for good agreement with the far-ﬁeld noise data. Our results indicate that excellent jet noise predictions are obtained using the asymptotic approach, remarkably, up to a Strouhal number of 0.5.

AB - In this study we show how accurate jet noise predictions can be achieved within Gold-stein’s generalized acoustic analogy formulation for heated and un-heated supersonic jets using a previously developed asymptotic theory for the adjoint vector Green’s function. In this approach, mean ﬂow non-parallelism enters the leading order dominant balance producing enhanced ampliﬁcation at low frequencies, which we believe corresponds to the peak sound at small polar observation angles. We determine all relevant mean ﬂow and turbulence quantities using Large Eddy Simulations of two axi-symmetric round jets at ﬁxed jet Mach number and diﬀerent nozzle temperature ratios. Certain empirical co-eﬃcients that enter the turbulence length scales formula are tuned for good agreement with the far-ﬁeld noise data. Our results indicate that excellent jet noise predictions are obtained using the asymptotic approach, remarkably, up to a Strouhal number of 0.5.

KW - jet noise predictions

KW - Gold-stein’s generalized acoustic analogy formulation

KW - adjoint vector Green’s function

KW - asymptotic approach

KW - turbulence

KW - mean flow

UR - https://stanford.app.box.com/s/dtch2qcvxzjkfa1a713x32eptg5fq0s5

UR - https://ctr.stanford.edu/proceedings-2016-summer-program

UR - https://ctr.stanford.edu/

M3 - Chapter

BT - Studying Turbulence using Numerical Simulation Databases - XVI

CY - Stanford, California

ER -