Model and full scale high-lift wing wind tunnel experiments dedicated to airframe noise reduction

Dobrzynski, W.; Gehlhar, B.; Buchholz, Heino

doi:10.1016/s1270-9638(00)01079-8

Cited by 41 publications

(18 citation statements)

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“…As a result a broadband noise reduction on the order of 2 to 3 dB was achieved with reference to the overall aircraft airframe noise level [9,10]. This result was found to hold true for the entire regime of radiation angles covered within this test.…”

Section: Quantitative Slat Noise Data Basementioning

confidence: 57%

“…Quantitative farfield noise data were obtained through noise testing on a 1/7.5 scaled complete model aircraft in DNW-LLF's 8 m x 6 m open test section [9,10].…”

Section: Quantitative Slat Noise Data Basementioning

confidence: 99%

“…In case the ratio between a source area A (scaling with the square of a characteristic geometric dimension) and the square of the radiation distance R is kept constant, then the squared farfield sound pressure as measured at model scale can be transposed to the full scale situation by the following simple relation: (10) [^M£del] = b^Zl = Scale Factor = SF L "Model L Thus the full scale high lift components design was close to that realized at model scale.…”

Section: Scaling Laws For Slat Noise Characteristicsmentioning

confidence: 99%

“…Although this comparison in the first place was meant to demonstrate that slat noise frequencies scale with geometric slat size, measured levels were also normalized according to Equ. (10), taking into account that in the full scale wing test only 40% of one wing span was exposed to the wind tunnel flow. Although the slat represents a line source, it should be emphasized again that an aircraft slat can not be treated as a 2-dimensional source, since it is composed from a series of uncorrelated sources of limited spanwise extent.…”

Section: Scaling Laws For Slat Noise Characteristicsmentioning

confidence: 99%

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Slat noise source studies for farfield noise prediction

Dobrzynski

Pott-Pollenske

2001

7th AIAA/CEAS Aeroacoustics Conference and Exhibit

115

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To-days low-noise high-bypass-ratio engines have made airframe noise for large commercial aircraft in the approach configuration to be compatible to that of the engines. As a consequence, flow noise from landing gears and from high lift devices (HLD) on wings -and its control -will become ever more important. In a study, dedicated to HLD flow noise, parametric wind tunnel experiments were performed on scaled wing sections in the Aeroacoustic Wind Tunnel Braunschweig, on a complete scale model aircraft and a full scale wingsection in the German-Dutch Wind Tunnel to identify relevant airframe noise mechanisms and develop noise prediction schemes. As one essential result of these tests deployed slats were identified as prominent noise contributors. Based on an extensive set of farfield noise data and on first results from measurements of the unsteady local flow properties in the slat area the effects of flow velocity and aircraft angle-of-attack on slat noise radiation characteristics were determined. The test results support the assumption that slat noise originates from the upper slat trailing-edge and scales with the slat cove vortex dimension. As a consequence the transposition of slat noise data from scale model tests towards a full scale situation can approximately be based on the geometric scale factor. Based on the findings of this experimental study a simplified source model is considered for slat noise prediction.

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Section: Quantitative Slat Noise Data Basementioning

confidence: 57%

“…Quantitative farfield noise data were obtained through noise testing on a 1/7.5 scaled complete model aircraft in DNW-LLF's 8 m x 6 m open test section [9,10].…”

Section: Quantitative Slat Noise Data Basementioning

confidence: 99%

Section: Scaling Laws For Slat Noise Characteristicsmentioning

confidence: 99%

Section: Scaling Laws For Slat Noise Characteristicsmentioning

confidence: 99%

See 2 more Smart Citations

Slat noise source studies for farfield noise prediction

Dobrzynski

Pott-Pollenske

2001

7th AIAA/CEAS Aeroacoustics Conference and Exhibit

115

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“…Additionally the present leading edge devices like slats have a high system complexity and omitting these systems provide a benefit in maintenance, costs and weight. Beyond this, especially slats are known to be the most significant source of airframe noise beside the landing gears in landing configuration of a transport aircraft 1 . On the other hand slats are a powerful passive device for achieving high values of maximum lift.…”

mentioning

confidence: 99%

Large-Scale Separation Flow Control Experiments Within the German Flow Control Network

Wild

Wichmann

Haucke

et al. 2009

47th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Airframe Noise – High Lift Device Noise

Zhang

2010

Encyclopedia of Aerospace Engineering

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High lift devices, together with landing gears, are the main sources of airframe noise during the approach‐and‐landing phase of aircraft flight. Typical high lift devices include leading edge slats and trailing edge flaps. Other high‐lift‐related noise‐generating devices include spoilers if deployed during a steep approach operation. All the above aerodynamic devices are retracted during the cruise phase of aircraft operation. A slat, when deployed, forms a cove region between the slat and the central main element of the aircraft wing. Flow separation, flow recirculation, an unsteady shear layer, and slat settings together generate noise of mainly broadband content. For a flap, the outboard flap side edge and vortex system associated with it are the main sources of noise. The intensity of high lift device noise generally follows a power law of flow velocity. The main sources of noise are identified and described in this chapter. Introduction is provided concerning main semi‐empirical and computational fluid dynamics methods. Noise attenuation methods are also described.

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Model and full scale high-lift wing wind tunnel experiments dedicated to airframe noise reduction

Cited by 41 publications

References 0 publications

Slat noise source studies for farfield noise prediction

Slat noise source studies for farfield noise prediction

Large-Scale Separation Flow Control Experiments Within the German Flow Control Network

Airframe Noise – High Lift Device Noise

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