An Integrated Design Approach for Low Noise Exposing High-Lift Devices

Wild, Jochen; Pott-Pollenske, Michael; Nagel, Björn

doi:10.2514/6.2006-2843

Cited by 55 publications

(33 citation statements)

References 8 publications

(7 reference statements)

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“…Note that this relation of coherence between slat and flap coves cannot be taken into account by simulations considering the dynamics of the slat cove. Farfield measurements by Wild et al (2006) W due to limited frequency resolution. Determination of the farfield acoustic radiation is an important study by itself and is therefore beyond the scope of the present study.…”

Section: Pressure Fluctuationsmentioning

confidence: 99%

“…Test case The study concerns a three-element aerofoil, which was tested in the low-speed wind tunnel (NWB) of DLR Braunschweig. The experimental results as well as the experimental apparatus and procedures are reported by Wild et al (2006) and Wild (2012). The model is based on the DLR-F15 two-dimensional profile, whose geometry is given in figure 2.…”

Section: Simulation Overviewmentioning

confidence: 99%

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Numerical investigation of the flow dynamics past a three-element aerofoil

Deck

Laraufie

2013

J. Fluid Mech.

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A numerical investigation of the flow dynamics around a two-dimensional high-lift configuration was carried out by means of a zonal detached eddy simulation (ZDES) technique for flow conditions corresponding to aircraft approach. Both slat and flap regions have been scrutinized and compared with experimental data available in the literature. It is shown that slat and flap coves behave like shallow cavities. The distance between the upstream cusp and the downstream edge is the relevant length scale for each cove taken separately. Consistently with previous findings, this study indicates that the maximum of the broadband spectrum of slat (respectively flap) pressure fluctuations occurs for Strouhal numbers 0.5 St 4 when based on slat chord (respectively on flap chord) and free-stream velocity. It is shown that mode (n) of the slat cove and mode (n + 1) of the flap cove are very close making a coherent phase relationship possible. A large-scale coupled self-sustained oscillations mechanism between slat and flap cavities, evidenced by spectral analysis, occurs at a Strouhal number St = 3-6 based on the main wing chord and free-stream velocity. This yields to an acoustic feedback mechanism characterized by a normalized frequency depending on the free stream Mach number like St = (1 − M 2 0 )/2M 0 . The present result appears to line up with the findings by Hein et al. (J. Fluid Mech., vol. 582, 2007, pp. 179-202) who showed that two types of resonance could exist: surface waves ones, scaling with the total aerofoil length and longitudinal cavity-type resonances, scaling with the slat cove length.

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Section: Pressure Fluctuationsmentioning

confidence: 99%

Section: Simulation Overviewmentioning

confidence: 99%

Numerical investigation of the flow dynamics past a three-element aerofoil

Deck

Laraufie

2013

J. Fluid Mech.

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“…The data shows that the computation concept for slat noise is valid and may be used for different slat designs. In Section 3.1.1 this method will be used to predict the noise reduction achieved by re-designing the slat to a so called "very long chord slat" (VLCS) [17]. A second noise reduction technology for high lift noise, which will be implemented in the overall assessment is the concept of a so called "slat cove liner", described in more detail in Section 3.1.2.…”

Section: Validity Of Level 1 Prediction For Slat Noise Reduction Techmentioning

confidence: 99%

Aircraft Noise Assessment—From Single Components to Large Scenarios

Delfs¹,

Bertsch²,

Zellmann

et al. 2018

Energies

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Abstract:The strategic European paper "Flightpath 2050" claims dramatic reductions of noise for aviation transport scenarios in 2050: ". . . The perceived noise emission of flying aircraft is reduced by 65%. These are relative to the capabilities of typical new aircraft in 2000. . . ". There is a consensus among experts that these far reaching objectives cannot be accomplished by application of noise reduction technologies at the level of aircraft components only. Comparably drastic claims simultaneously expressed in Flightpath 2050 for carbon dioxide and NOX reduction underline the need for step changes in aircraft technologies and aircraft configurations. New aircraft concepts with entirely different propulsion concepts will emerge, including unconventional power supplies from renewable energy sources, ranging from electric over hybrid to synthetic fuels. Given this foreseen revolution in aircraft technology the question arises, how the noise impact of these new aircraft may be assessed. Within the present contribution, a multi-level, multi-fidelity approach is proposed which enables aircraft noise assessment. It is composed by coupling noise prediction methods at three different levels of detail. On the first level, high fidelity methods for predicting the aeroacoustic behavior of aircraft components (and installations) are required since in the early stages of the development of innovative noise reduction technology test data is not available. The results are transferred to the second level, where radiation patterns of entire conventional and future aircraft concepts are assembled and noise emissions for single aircraft are computed. In the third level, large scale scenarios with many aircraft are considered to accurately predict the noise exposure for receivers on the ground. It is shown that reasonable predictions of the ground noise exposure level may be obtained. Furthermore, even though simplifications and omissions are introduced, it is shown that the method is capable of transferring all relevant physical aspects through the levels.

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“…This modelling technique has been assessed on the LEISA three-element aerofoil designed by DLR [31]. The zonal strategy retained and the modes used for this simulation are depicted in the upper part of figure 4.…”

Section: (A) Low-speed Conditionsmentioning

confidence: 99%

High-fidelity simulations of unsteady civil aircraft aerodynamics: stakes and perspectives. Application of zonal detached eddy simulation

Deck

Gand

Brunet

et al. 2014

Phil. Trans. R. Soc. A.

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This paper provides an up-to-date survey of the use of zonal detached eddy simulations (ZDES) for unsteady civil aircraft applications as a reflection on the stakes and perspectives of the use of hybrid methods in the framework of industrial aerodynamics. The issue of zonal or non-zonal treatment of turbulent flows for engineering applications is discussed. The ZDES method used in this article and based on a fluid problem-dependent zonalization is briefly presented. Some recent landmark achievements for conditions all over the flight envelope are presented, including low-speed (aeroacoustics of high-lift devices and landing gear), cruising (engine-airframe interactions), propulsive jets and off-design (transonic buffet and dive manoeuvres) applications. The implications of such results and remaining challenges in a more global framework are further discussed.

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An Integrated Design Approach for Low Noise Exposing High-Lift Devices

Cited by 55 publications

References 8 publications

Numerical investigation of the flow dynamics past a three-element aerofoil

Numerical investigation of the flow dynamics past a three-element aerofoil

Aircraft Noise Assessment—From Single Components to Large Scenarios

High-fidelity simulations of unsteady civil aircraft aerodynamics: stakes and perspectives. Application of zonal detached eddy simulation

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