Theoretical Modelling Of Broadband Shock Associated Noise in Asymmetric Jets

Kalyan, Anuroopa; Karabasov, Sergey A.

doi:10.2514/6.2015-3127

Cited by 4 publications

(13 citation statements)

References 8 publications

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“…Further validation details for the static pressure profiles in the same jet flow region can be obtained in Kalyan and Karabasov [9].…”

Section: Axisymmetric Jet Modelling 41 Flow-field Resultsmentioning

confidence: 99%

“…. The acoustic time scale is defined in accordance with (8,9). The space scale is related to the time scale in accordance with the relation suggested by Frendi et.…”

Section: Mixed Scale Modelmentioning

confidence: 87%

“…The constants have the values as: α =2.0; = 5.25; = 1.25 and ┴ = 0.25. Following Kalyan and Karabasov [9], these parameters have been obtained by matching the model predictions with respect to the far-field sound spectra data from the experiment for one jet condition and one observer angle and then keeping the model calibration parameters constant for all other jet cases and observer angles.…”

Section: Mixed Scale Modelmentioning

confidence: 99%

“…A way to reduce BBSAN is to diminish the shock cell -turbulence interaction by weakening the strength of the shock cells through breaking the axisymmetry of the jet flow. To study these effects for each baseline case of the axisymmetric convergent-divergent and convergent jets, this section considers several generic elliptic jets of varying eccentricity from Kalyan and Karabasov [9]. The jets correspond to different aspect ratios (AR), viz., 1.5, 2.0 and 3.0 but the same nozzle exit area and jet velocity at the nozzle exit as for the baseline axisymmetric jets so that the thrust is maintained the same.…”

Section: Asymmetric Jetsmentioning

confidence: 99%

“…The last conceptual step of the model is to evaluate the correlation scales and the amplitude by linearly scaling the characteristic turbulence scales obtainable from a RANS solution with some constant calibration parameters that are typically evaluated from matching the model predictions to the far-field noise data. For instance, for a k-epsilon RANS model, the characteristic space and time scales can be linked to the corresponding RANS turbulent kinetic energy and the energy dissipation rate distributions as implemented in the original model by Morris and Miller [6] and their model implementation by Kalyan and Karabasov [9].…”

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confidence: 99%

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Broad band shock associated noise predictions in axisymmetric and asymmetric jets using an improved turbulence scale model

Kalyan

Karabasov

2017

Journal of Sound and Vibration

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Supersonic jets that are subject to off-design operating conditions are marked by three distinct regions in their far-field spectra: mixing noise, screech and Broadband Shock Associated Noise (BBSAN). BBSAN is conspicuous by the prominent multiple peaks. The Morris and Miller BBSAN model that is based on an acoustic analogy, offering a straightforward implementation for RANS, forms the foundation of the present work. The analogy model robustly captures the peak frequency noise, that occurs near Strouhal number of about 1, based on the nozzle exit diameter but leads to major sound under prediction for higher frequencies. In the jet mixing noise literature, it has been shown that an inclusion of frequency dependence into the characteristic length and temporal scales of the effective noise sources improves the far-field noise predictions. In the present paper, several modifications of the original Morris and Miller model are considered that incorporate the frequency dependent scales as recommended in the jet mixing noise literature. In addition to these, a new mixed scale model is proposed that incorporates a correlation scale that depends both on the mean-flow velocity gradient and the standard mixing noise-type scaling based on the dissipation of turbulent kinetic energy. In comparison with the original Morris and Miller model, the mixed scale model shows considerable improvements in the noise predictions for the benchmark axisymmetric convergent-divergent and convergent jets. Further to this validation, the new model has been applied for improved predictions for elliptic jets of various eccentricity. It has been shown that,

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“…Further validation details for the static pressure profiles in the same jet flow region can be obtained in Kalyan and Karabasov [9].…”

Section: Axisymmetric Jet Modelling 41 Flow-field Resultsmentioning

confidence: 99%

“…. The acoustic time scale is defined in accordance with (8,9). The space scale is related to the time scale in accordance with the relation suggested by Frendi et.…”

Section: Mixed Scale Modelmentioning

confidence: 87%

Section: Mixed Scale Modelmentioning

confidence: 99%

Section: Asymmetric Jetsmentioning

confidence: 99%

mentioning

confidence: 99%

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Broad band shock associated noise predictions in axisymmetric and asymmetric jets using an improved turbulence scale model

Kalyan

Karabasov

2017

Journal of Sound and Vibration

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Effect of non-parallel mean flow on the acoustic spectrum of heated supersonic jets: Explanation of “jet quietening”

2019

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Noise measurements of heated axisymmetric jets at fixed supersonic acoustic Mach number indicate that the acoustic spectrum reduces when the temperature ratio increases. The 'spectral quietening' effect has been observed both experimentally and computationally using Large Eddy Simulations (LES). It was explained by Afsar et al. (M. Z. Afsar and M. E. Goldstein & A. M. Fagan AIAAJ., Vol. 49, p. 2522, 2011) through the cancellation introduced by enthalpy flux/momentum flux coupling term using the generalized acoustic analogy formulation. But the parallel flow assumption is known to give inaccurate predictions at high jet speeds. In this paper we therefore extend the non-parallel flow asymptotic theory of Goldstein et al.

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Towards a Suitable Turbulence Length and Temporal Scale Model for Broadband Shock Associated Noise

Kalyan

Karabasov

2016

22nd AIAA/CEAS Aeroacoustics Conference

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Theoretical Modelling Of Broadband Shock Associated Noise in Asymmetric Jets

Cited by 4 publications

References 8 publications

Broad band shock associated noise predictions in axisymmetric and asymmetric jets using an improved turbulence scale model

Broad band shock associated noise predictions in axisymmetric and asymmetric jets using an improved turbulence scale model

Effect of non-parallel mean flow on the acoustic spectrum of heated supersonic jets: Explanation of “jet quietening”

Towards a Suitable Turbulence Length and Temporal Scale Model for Broadband Shock Associated Noise

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