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

Miller, Steven A.; Morris, Philip J.

doi:10.2514/6.2010-3730

Cited by 8 publications

(4 citation statements)

References 15 publications

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“…This behavior is shown by the present predictions with a model that does not include the influence of the mean flow refraction effects on the BBSAN. Miller and Morris [20] show that the mean flow effects in dual-stream jets for sources in the outer shear layer are negligible. However, mean flow effects cannot be ignored for the inner shear layer, as sound from these sources must propagate through the outer high-speed stream.…”

Section: A Single-stream Axisymmetric Jetsmentioning

confidence: 99%

Prediction of Broadband Shock-Associated Noise Using Reynolds-Averaged Navier-Stokes Computational Fluid Dynamics

Morris

Miller

2010

AIAA Journal

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Broadband shock-associated noise is a component of jet noise generated by supersonic jets operating offdesign. It is characterized by multiple broadband peaks and dominates the total noise at large angles to the jet downstream axis. A new model is introduced for the prediction of broadband shock-associated noise that uses the solution of the Reynolds-averaged Navier-Stokes equations. The noise model is an acoustic analogy based on the linearized Euler equations. The equivalent source terms depend on the product of the fluctuations associated with the jet's shock-cell structure and the turbulent velocity fluctuations in the jet shear layer. The former are deterministic and are obtained from the Reynolds-averaged Navier-Stokes solution. A statistical model is introduced to describe the properties of the turbulence. Only the geometry and operating conditions of the nozzle need to be known to make noise predictions. This overcomes the limitations and empiricism present in previous broadband shock-associated noise models. Results for various axisymmetric circular nozzles and a rectangular nozzle operating at various conditions are compared with experimental data to validate the model.

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Section: A Single-stream Axisymmetric Jetsmentioning

confidence: 99%

Prediction of Broadband Shock-Associated Noise Using Reynolds-Averaged Navier-Stokes Computational Fluid Dynamics

Morris

Miller

2010

AIAA Journal

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“…The model by Morris and Miller [4] has been applied to dualstream and rectangular jets by Miller and Morris [14]. This work demonstrated the first BBSAN predictions of dualstream jets using an acoustic analogy.…”

Section: Introductionmentioning

confidence: 93%

“…This is due to the refraction effects of the secondary stream shear layer. Miller and Morris [14] also demonstrated the first rectangular nozzle BBSAN predictions based on SRANS solutions. The developed model equation makes no assumption regarding the geometry of the nozzle and is not limited to rectangular or circular geometries.…”

Section: Introductionmentioning

confidence: 98%

The Prediction of Broadband Shock-Associated Noise Including Propagation Effects

Miller

Morris

2012

International Journal of Aeroacoustics

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An acoustic analogy is developed based on the Euler equations for broadband shockassociated noise (BBSAN) that directly incorporates the vector Green's function of the linearized Euler equations and a steady Reynolds-Averaged Navier-Stokes solution (SRANS) as the mean flow. The vector Green's function allows the BBSAN propagation through the jet shear layer to be determined. The large-scale coherent turbulence is modeled by two-point second order velocity cross-correlations. Turbulent length and time scales are related to the turbulent kinetic energy and dissipation. An adjoint vector Green's function solver is implemented to determine the vector Green's function based on a locally parallel mean flow at streamwise locations of the SRANS solution. However, the developed acoustic analogy could easily be based on any adjoint vector Green's function solver, such as one that makes no assumptions about the mean flow. The newly developed acoustic analogy can be simplified to one that uses the Green's function associated with the Helmholtz equation, which is consistent with the formulation of Morris and Miller (AIAAJ 2010). A large number of predictions are generated using three different nozzles over a wide range of fully expanded Mach numbers and jet stagnation temperatures. These predictions are compared with experimental data from multiple jet noise labs. In addition, two models for the so-called 'fine-scale' mixing noise are included in the comparisons. Improved BB-SAN predictions are obtained relative to other models that do not include the propagation effects, especially in the upstream direction of the jet.

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“…A first assessment of the requirements has been performed based on the case already investigated experimentally by Viswanathan et al [13] and numerically by Miller and Morris [14]. The initial flow parameters for the coaxial jet are M 1 = 0.71 and M 2 = 1.36 for the primary and secondary flow, respectively.…”

Section: Facility Design Processmentioning

confidence: 99%

Design of a Facility for Studying Shock-Cell Noise on Single and Coaxial Jets

2018

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Shock-cell noise occurs in aero-engines when the nozzle exhaust is supersonic and shock-cells are present in the jet. In commercial turbofan engines, at cruise, the secondary flow is often supersonic underexpanded, with the formation of annular shock-cells in the jet and consequent onset of shock-cell noise. This paper aims at describing the design process of the new facility FAST (Free jet AeroacouSTic laboratory) at the von Karman Institute, aimed at the investigation of the shock-cell noise phenomenon on a dual stream jet. The rig consists of a coaxial open jet, with supersonic capability for both the primary and secondary flow. A coaxial silencer was designed to suppress the spurious noise coming from the feeding lines. Computational fluid dynamics (CFD) simulations of the coaxial jet and acoustic simulations of the silencer have been carried out to support the design choices. Finally, the rig has been validated by performing experimental measurements on a supersonic single stream jet and comparing the results with the literature. Fine-scale PIV (Particle Image Velocimetry) coupled with a microphone array in the far field have been used in this scope. Preliminary results of the dual stream jet are also shown.

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

Cited by 8 publications

References 15 publications

Prediction of Broadband Shock-Associated Noise Using Reynolds-Averaged Navier-Stokes Computational Fluid Dynamics

Prediction of Broadband Shock-Associated Noise Using Reynolds-Averaged Navier-Stokes Computational Fluid Dynamics

The Prediction of Broadband Shock-Associated Noise Including Propagation Effects

Design of a Facility for Studying Shock-Cell Noise on Single and Coaxial Jets

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