The Prediction of Broadband Shock-Associated Noise Using RANS CFD

Morris, Philip J.; Miller, Steven A.

doi:10.2514/6.2009-3315

Cited by 11 publications

(32 citation statements)

References 12 publications

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“…In comparison with the Harper-Bourne and Fisher model [2], the latter models are much more theory grounded as compared to the earlier work: they employed stochastic modelling to describe the effect of turbulence and the Pack-Prandtl theory [5] to model the shock cell structure. As a further development, Morris and Miller [6] proposed a BBSAN prediction scheme that is made specific to nozzle geometry by considering the development of the jet flow, including modelling of internal flow in the nozzle with the use of a two-equation RANS solution. The model is advantageous in the sense that it only requires the knowledge of two parameters that govern the jet flow, nozzle pressure ratio (NPR) and the total temperature ratio (TTR).…”

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confidence: 99%

“…For coupling acoustic modelling with the flow solution, the Morris and Miller model [6] uses the triple scale flow solution decomposition in the framework of the classical Lighthill acoustic analogy approach [7]. In the acoustic analogy model, the flow is decomposed into the steady mean-flow solution, turbulence fluctuations, and acoustic fluctuations.…”

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confidence: 99%

“…The covariance function needed for BBSAN description is more complex than the second-order velocity auto-correlation functions that are relatively routinely measured in experiments or obtained from eddy-resolving computations. Hence, the first step of the Morris and Miller source model [6] is to factor out the effect of spatially variable mean-flow gradient from the effective source function to reduce the source function to the conventional second-order velocity auto-correlation function form which is further simplified by taking into account sound radiating in the far-field observer direction.…”

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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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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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“…The full details are presented in Morris and Miller 13 or Miller. 14 The BBSAN model builds on the analysis of Tam 4 and is considerably simplified by using the inviscid compressible equations of motion,…”

Section: Methodology and Implementationmentioning

confidence: 99%

The Prediction of Broadband Shock-Associated Noise from Dualstream and Rectangular Jets Using RANS CFD

Miller

Morris

2010

16th AIAA/CEAS Aeroacoustics Conference

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Supersonic jets operating off-design produce broadband shock-associated noise. Broadband shock-associated noise is characterized by multiple broadband peaks in the far-field and is often the dominant source of noise towards the sideline and upstream direction relative to the jet axis. It is due to large scale coherent turbulence structures in the jet shear layers interacting with the shock cell structure. A broadband shock-associated noise model recently developed by the authors predicts this noise component from solutions to the Reynolds averaged Navier-Stokes equations using a two-equation turbulence model. The broadband shock-associated noise model is applied to dualstream and rectangular nozzles operating supersonically, heated, and off-design. The dualstream jet broadband shock-associated noise predictions are conducted for cases when the core jet is supersonic and the fan jet is subsonic, the core jet is subsonic and the fan jet is supersonic, and when both jet streams operate supersonically. Rectangular jet predictions are shown for a convergent-divergent nozzle operating both over-and under-expanded for cold and heated conditions. The original model implementation has been heavily modified to make accurate predictions for the dualstream jets. It is also argued that for over-expanded jets the oblique shock wave attached to the nozzle lip contributes little to broadband shock-associated noise. All predictions are compared with experiments.

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“…This phenomenon has been studied in great detail for free jets. [11][12][13][14][15] It has previously been noted that turbulent Coanda wall jets display at least some similar characteristics to their two-dimensional counterparts, and thus in order to facilitate a preliminary investigation into the nature and behavior of SAN in Coanda flows, this simplifying assumption will be made. 7 However, when the flow is three-dimensional, complicating factors such as radial expansion and streamline curvature are present, and should be accounted for in future models.…”

Section: Shock Associated Noise (San)mentioning

confidence: 99%