Toward a Comprehensive Model of Jet Noise Using an Acoustic Analogy

Miller, Steven A.

doi:10.2514/1.j052809

Cited by 22 publications

(13 citation statements)

References 47 publications

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“…Though the model will not capture the characteristic "negative loops" observed in measurement, the proposed model is consistent with Tam and Auriault [41]. Morris and Farassat [42] and Miller [43] also demonstrated accurate predictions relative to measurement using this model. The selection of this model also allows the derivatives and integrals with respect to time and space to be performed analytically and yields appropriate powers of ω that are consistent with Tam and Auriault [41], Morris and Farassat [42], and Miller [43].…”

Section: Modeling the Two-point Cross Correlation Of The Lighthill Stsupporting

confidence: 54%

“…Morris and Farassat [42] and Miller [43] also demonstrated accurate predictions relative to measurement using this model. The selection of this model also allows the derivatives and integrals with respect to time and space to be performed analytically and yields appropriate powers of ω that are consistent with Tam and Auriault [41], Morris and Farassat [42], and Miller [43]. Furthermore, by choosing to use the coefficient matrix A ijlm , the potential to include anisotropic effects of turbulence is possible.…”

Section: Modeling the Two-point Cross Correlation Of The Lighthill Stmentioning

confidence: 68%

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Prediction of Near-Field Jet Cross Spectra

Miller

2015

AIAA Journal

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A prediction method is developed based on the acoustic analogy for the cross-power spectral density in the convecting near field of compressible fluid turbulence. Equivalent source near-field, midfield, and far-field terms within the model integrand create corresponding near-field, midfield, and far-field radiating waves. These equivalent sources are modeled with a single equation for the two-point cross correlation of the Lighthill stress tensor that is dependent on the jet operating conditions. An alternative equivalent source model based on steady Reynoldsaveraged Navier-Stokes solutions is proposed. The cross-power spectral density model automatically reduces to a traditional autopower spectral density model when observers are at the same location. Predictions of radiation intensity and coherence compare favorably with measurements in the near field, midfield, and far field for a wide range of jet Mach numbers and temperature ratios.fully expanded jet diameter e s = number of ensembles F t = far-field integrand terms f = frequency G = cross-power spectral density g = Green's function k = turbulent kinetic energy l si = turbulent length scale M = Mach number M c = convective Mach number coefficient M d = design Mach number M j = fully expanded Mach number M t = midfield integrand terms M ∞;i = component of the vector freestream Mach number N t = near-field integrand terms P f = prefactor Pr = Prandtl number Pr t = turbulent Prandtl number p = pressure R = magnitude of x R g = gas constant R ijlm = two-point cross correlation of T ij r = source vector S = spectral density S ij = source tensor S y = equivalent spatial source distribution St = Strouhal number T ij = Lighthill stress tensor T j = fully expanded temperature t = time u = velocity vector u j = fully expanded jet velocity x = observer spatial coordinate y = source spatial coordinate y c = core length α = constant length scale coefficient β s= ratio of specific heats δ = Dirac delta function δ ij = Kronecker delta function ϵ = dissipation of turbulent kinetic energy ηξ; η; ζ = vector within source region ρ = density σ = anisotropic dependence parameter σ f = anisotropic amplification exponent τ = retarded time τ s = turbulent time scale ϕ = azimuthal observer angle Ψ = inlet observer angle ω = radial frequency

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Section: Modeling the Two-point Cross Correlation Of The Lighthill Stsupporting

confidence: 54%

Section: Modeling the Two-point Cross Correlation Of The Lighthill Stmentioning

confidence: 68%

Prediction of Near-Field Jet Cross Spectra

Miller

2015

AIAA Journal

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“…Absorbing media have been treated 157 using LEE in combination with a discontinuous Galerkin framework. With increasing computational resources, LEE has been established as a propagation tool of choice with applications to jet noise, 158,159 airframe noise, 54,160 and cavity sound computations. 161,162 Upon this, advances have been established to include particular effects in aeroacoustic modeling.…”

Section: Linearized Eulermentioning

confidence: 99%

Hybrid Aeroacoustic Computations: State of Art and New Achievements

Schoder

2019

J. Theor. Comp. Acout.

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This paper collects the state of the art and the tremendous progress that has been made in hybrid modeling of aeroacoustic sound. Hybrid modeling is defined such that flow and acoustics are modeled separate and connected by an aeroacoustic model. The contributions will be classified with respect to the aeroacoustic models being developed, covering Lighthill’s analogy, Ffowcs Williams and Hawkings, vortex sound, linearized Euler equations (LEE), and different perturbation equations modeling flow induced sound. Within each topic, specific applications, such as jet noise, aircraft noise, ground mobility, noise, fan noise and human phonation, are covered. We focus on the accomplishments and provide the authors’ contribution to aeroacoustic research. Eventually, a concise summary of the different methods and their capabilities is included.

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“…Non-linear propagation effects can be accounted for by solving a simplified set of equations that govern the acoustic field [10,11]. The computational cost associated with LES and DES is still significant; steady Reynolds-Averaged Navier-Stokes (RANS) solvers with a k− [12] or k−ω [3,4] turbulence closure model may be favoured for rapid acoustic predictions [3,[12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Correlation Analysis of High-Resolution Particle Image Velocimetry Data of Screeching Jets

Tan¹,

Honnery²,

Kalyan

et al. 2019

AIAA Journal

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The acoustic analogy provides a general framework for predicting broadband jet noise. The accuracy of the noise predictions are strongly dependent on the second-and fourth-order integral time and length scales of the turbulence quantities in the jet. Two low-order models for the second-and fourth-order integral length scales are examined. The low-order models are defined by locally isotropic scales estimated from 2D particle image velocimetry measurements. These measurements are of screeching underexpanded unheated round jets issuing from a purely converging nozzle at conditions, which corresponds to ideally expanded Mach numbers of 1.45 and 1.59. The jets are dominated by the helical C instability screech mode, which is associated with large-scale coherent periodic fluctuations. These fluctuations are filtered using a proper orthogonal decomposition method to assess low-order models that approximate the length scales associated with the broadband noise mechanisms. The length scale model parameters are shown to be insensitive for the two Mach numbers considered. The root-mean-square error associated with the low-order models indicates that either is sufficient for approximating the integral length scales required to model equivalent sources of broadband jet noise.

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Toward a Comprehensive Model of Jet Noise Using an Acoustic Analogy

Cited by 22 publications

References 47 publications

Prediction of Near-Field Jet Cross Spectra

Prediction of Near-Field Jet Cross Spectra

Hybrid Aeroacoustic Computations: State of Art and New Achievements

Correlation Analysis of High-Resolution Particle Image Velocimetry Data of Screeching Jets

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