Jet and wing/flap interaction noise

Brown, W. H.; Ahuja, K. K.

doi:10.2514/6.1984-2362

Cited by 23 publications

(13 citation statements)

References 2 publications

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“…Thus, we see that there is a marginal beneficial effect up to 1 dB with the R-flaperon especially in the front quadrant at lower frequencies. Recall that earlier studies 10,6 have denoted this region also as the one dominated by JFI. We will corroborate this later with phased array analysis.…”

Section: Resultsmentioning

confidence: 99%

“…In terms of experiments on jet-flap interaction noise useful to our study, we make note of the work in SenGupta 5 and Brown/Ahuja 6 . SenGupta analyzes both jet-wing interaction noise and jet-flap interaction noise: the first one is defined when the flaps are not deflected and is modeled in terms of lift fluctuation noise, trailing edge noise, and jet noise reflection; the second one, JFI noise, is defined as the additional component purely due to flap deflection and is modeled in terms of lift fluctuations on the flaps diffracted by the wing trailing edge.…”

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confidence: 99%

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Flaperon Modification Effect on Jet-Flap Interaction Noise Reduction for Chevron Nozzles

Mengle

Stoker

Brusniak

et al. 2007

13th AIAA/CEAS Aeroacoustics Conference (28th AIAA Aeroacoustics Conference)

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Jet-flap interaction (JFI) noise can become an important component of far field noise when a flap is immersed in the engine propulsive stream or is in its entrained region, as in approach conditions for under-the-wing engine configurations. We experimentally study the effect of modifying the flaperon, which is a high speed aileron between the inboard and outboard flaps, at both approach and take-off conditions using scaled models in a free jet. The flaperon modifications were of two types: sawtooth trailing edge and mini vortex generators (vg's). Parametric variations of these two concepts were tested with a round coaxial nozzle and an advanced chevron nozzle, with azimuthally varying fan chevrons, using both far field microphone arrays and phased microphone arrays for source diagnostics purposes. In general, the phased array results corroborated the far field results in the upstream quadrant pointing to JFI near the flaperon trailing edge as the origin of the far field noise changes. Specific sawtooth trailing edges in conjunction with the round nozzle gave marginal reduction in JFI noise at approach, and parallel co-rotating mini-vg's were somewhat more beneficial over a wider range of angles, but both concepts were noisier at take-off conditions. These two concepts had generally an adverse JFI effect when used in conjunction with the advanced chevron nozzle at both approach and take-off conditions. Nomenclature

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Flaperon Modification Effect on Jet-Flap Interaction Noise Reduction for Chevron Nozzles

Mengle

Stoker

Brusniak

et al. 2007

13th AIAA/CEAS Aeroacoustics Conference (28th AIAA Aeroacoustics Conference)

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“…There is a body of literature on past experimental studies of trailing-edge noise and jet-wing and jet-flap interaction noise (e.g. Tam & Yu 1975;Yu & Tam 1978;Olsen & Boldman 1979;Way & Turner 1980;Miller 1983;SenGupta 1983;Brown & Ahuja 1984;Mead & Strange 1998;Mengle 2011). For a review of past analytical as well as experimental efforts in these areas an interested reader may refer to Crighton (1991).…”

Section: Introductionmentioning

confidence: 99%

An experimental investigation of resonant interaction of a rectangular jet with a flat plate

et al. 2015

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The interaction between an 8:1 aspect ratio rectangular jet and a flat plate, placed parallel to the jet, is addressed in this study. At high subsonic conditions and for certain relative locations of the plate, a resonance takes place with accompanying audible tones. Even when the tone is not audible the sound pressure level spectra are often marked by conspicuous peaks. The frequencies of these peaks, as functions of the plate's length, its location relative to the jet as well as jet Mach number, are studied in an effort to understand the flow mechanism. It is demonstrated that the tones are not due to a simple feedback between the nozzle exit and the plate's trailing edge; the leading edge also comes into play in determining the frequency. With parametric variation, it is found that there is an order in the most energetic spectral peaks; their frequencies cluster in distinct bands. The lowest frequency band is explained by an acoustic feedback involving diffraction at the plate's leading edge. Under the resonant condition, a periodic flapping motion of the jet column is seen when viewed in a direction parallel to the plate. Phase-averaged Mach number data on a cross-stream plane near the plate's trailing edge illustrate that the jet cross-section goes through large contortions within the period of the tone. Farther downstream a clear 'axis switching' takes place for the time-averaged cross-section of the jet that does not occur otherwise for a non-resonant condition.

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“…Investigations of influence of installation effects on jet noise and flow-field is being conducted during last thirty years [1][2][3][4][5][6][7][8]. The analysis of obtained results is given in [4][5] in detail.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of Jet Flap Interaction Effects

Lyubimov

Maslov

Mironov

et al. 2014

International Journal of Aeroacoustics

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The influence of the wing and flaps geometry on the flow field and acoustic radiation of the jet are experimentally and numerically investigated. The azimuth non-uniformity of jet acoustic field was experimentally defined with a help of far-field microphones, flow field within the jet was measured using PIV technique and numerically calculated with a help high resolution combined RANS/ILES method. The jet flaps interaction (JFI) effects was experimentally and numerically investigated at facility under modeling of real bypass nozzle configuration and outflow parameters. The comparison between measured flow-field and noise of a jet shows that JFI excess noise is mainly related to jet deformation and increasing of velocity gradients and turbulence within jet which are induced by tip flap vortexes. NOMENCLATURE D: Diameter of nozzle (cm). U: Jet velocity (m/s). T: Total jet temperature (K). a: Angle of flap inclination (°). a 1 : Angle of wing attack (°). q: Polar noise emission angle relative to jet axis (°). F: Azimuth noise emission angle (°). f: 1/3-octave center frequency (Hz). M e : External outflow Mach number. NPR-Nozzle Pressure Ratio. BPR-ByPass Ratio JFI-Jet Flaps Interaction. SPL: Sound Pressure Level (dB). OASPL: Overall Sound Pressure Level (dB). Subscripts c and f denote core and fan counters of the nozzle.

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Jet and wing/flap interaction noise

Cited by 23 publications

References 2 publications

Flaperon Modification Effect on Jet-Flap Interaction Noise Reduction for Chevron Nozzles

Flaperon Modification Effect on Jet-Flap Interaction Noise Reduction for Chevron Nozzles

An experimental investigation of resonant interaction of a rectangular jet with a flat plate

Experimental and Numerical Investigation of Jet Flap Interaction Effects

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