Airframe noise characteristics of a 4.7 percent scale DC-10 model

Hayes, Julie; Horne, William C.; Soderman, P. T.; Bent, Paul

doi:10.2514/6.1997-1594

Cited by 68 publications

(27 citation statements)

References 2 publications

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“…The ranking of these sources is configuration dependent; typically, noise due to high-lift system dominates for the medium sized aircraft, whereas landing gear noise could be more important for the larger twin-engine transports. Model scale tests [1][2][3][4][5][6] have identified the leading-edge slat as a prominent source of airframe noise during approach conditions. These findings are corroborated by the flyover noise measurements for the Airbus A340 7 .…”

Section: Introductionmentioning

confidence: 99%

Slat Cove Unsteadiness: Effect of 3D Flow Structures

Choudhari

Khorrami

2006

44th AIAA Aerospace Sciences Meeting and Exhibit

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Our previous studies have indicated that 2D, time accurate computations based on a pseudo-laminar zonal model of the slat cove region (within the framework of the Reynolds-Averaged Navier-Stokes equations) are inadequate for predicting the full unsteady dynamics of the slat cove flow field. Even though such computations could capture the large-scale, unsteady vorticity structures in the slat cove region without requiring any external forcing, the simulated vortices were excessively strong and the recirculation zone was unduly energetic in comparison with the PIV measurements for a generic high-lift configuration. To resolve this discrepancy and to help enable physics based predictions of slat aeroacoustics, the present paper is focused on 3D simulations of the slat cove flow over a computational domain of limited spanwise extent. Maintaining the pseudo-laminar approach, current results indicate that accounting for the threedimensionality of flow fluctuations leads to considerable improvement in the accuracy of the unsteady, nearfield solution. Analysis of simulation data points to the likely significance of turbulent fluctuations near the reattachment region toward the generation of broadband slat noise. The computed acoustic characteristics (in terms of the frequency spectrum and spatial distribution) within short distances from the slat resemble the previously reported, subscale measurements of slat noise.

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Section: Introductionmentioning

confidence: 99%

Slat Cove Unsteadiness: Effect of 3D Flow Structures

Choudhari

Khorrami

2006

44th AIAA Aerospace Sciences Meeting and Exhibit

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“…(19), aredefinedhereas the causality spectra associated withthesurface area elements AS(y) and represent their contribution to the total noise G,,.…”

Section: The Average Values Ofmentioning

confidence: 99%

“…Equation (19) In those practical application cases where AS(y) must be finite in size and limited in number, the validity of Eq. (19) requires that AS(y) be chosen and To account for the "half-baffle" acoustic effect of the inboard surfaces, the solution can be multiplied by a factor of two (2). This should give an accurate presentation for small 0".…”

Section: The Average Values Ofmentioning

confidence: 99%

Flap edge aeroacoustic measurements and predictions

Brooks

Humphreys

2000

6th Aeroacoustics Conference and Exhibit

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“…The ranking of these sources is configuration dependent; however, both model-scale tests [1][2][3][4][5][6] and flyover noise measurements 7 have identified the leading-edge slat as a prominent source of airframe noise during aircraft approach. The slat noise spectrum is typically broadband, but may include one or more narrower peaks associated with aerodynamic and/or aeroacoustic resonances.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Realistic Reynolds Numbers on Slat Noise Simulations

Lockard

Choudhari

2012

18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference)

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The slat noise from the 30P/30N high-lift system has been computed using a computational fluid dynamics code in conjunction with a Ffowcs Williams-Hawkings solver. Varying the Reynolds number from 1.71 to 12.0 million based on the stowed chord resulted in slight changes in the radiated noise. Tonal features in the spectra were robust and evident for all Reynolds numbers and even when a spanwise flow was imposed. The general trends observed in near-field fluctuations were also similar for all the different Reynolds numbers. Experiments on simplified, subscale high-lift systems have exhibited noticeable dependencies on the Reynolds number and tripping, although primarily for tonal features rather than the broadband portion of the spectra. Either the 30P/30N model behaves differently, or the computational model is unable to capture these effects. Hence, the results underscore the need for more detailed measurements of the slat cove flow.

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Airframe noise characteristics of a 4.7 percent scale DC-10 model

Cited by 68 publications

References 2 publications

Slat Cove Unsteadiness: Effect of 3D Flow Structures

Slat Cove Unsteadiness: Effect of 3D Flow Structures

Flap edge aeroacoustic measurements and predictions

The Influence of Realistic Reynolds Numbers on Slat Noise Simulations

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