Measurements of 26%-Scale 777 Airframe Noise in the NASA Ames 40- by 80 Foot Wind Tunnel

Aeroacoustic Study of a High-Fidelity Aircraft Model: Part 1-Steady Aerodynamic Measurements

“…Acoustic measurements from flight tests [1][2][3][4][5][6] and model-scale experiments 7,8 have identified the undercarriage system and the high-lift devices, such as slats and flaps, as prominent airframe noise sources. The environmental noise impact of the civil transport fleet during landing and take-off operations must be reduced to meet increasingly stringent community noise regulations.…”

Experimental Investigation of Flow Around Three-Element High-Lift Airfoil with Morphing Fillers

“…The slat cove filler profiles were derived from CFD analysis in order to maintain attached flow on the slat lower surface. From the experiments it was shown that slat cove filler was effective in reducing broadband slat noise upto 4-5 dB [9] that was measured using a microphone phased array. However no aerodynamic measurements were presented in this study.…”

“…Eventhough several studies [9][10][11][12][13][14][15][16][17][18] have been performed on the noise reduction capabilities of the slat cove filler, only basic aerodynamic and noise measurements have been presented. A detailed experimental study of the aerodynamic performance characteristics such as surface pressure measurements, shear layer measurements and the interaction confluent wakes of all the three-element of the high-lift airfoil has not yet been reported.…”

“…Several experimental and computational studies [9][10][11][12][13][14][15][16][17][18] were made over the past decade to reduce the broadband noise arising from the slat cove region by filling the recirculation area within the slat cove gap. Even though reduction in broadband noise was observed at all the instances it has been a challenge to maintain the aerodynamic performance of the high-lift device for the cove filled configurations.…”

Effects of Geometric Details on Slat Noise Generation and Propagation

“…Slat cove cover 3 and slat cove filler [20][21] modifications that either delay or altogether remove shear layer formation have been shown to reduce the broadband noise by 3-4dB. The effectiveness of these noise reduction concepts underscores the importance of the cove flow originating at the cusp and how its alteration may provide substantial noise benefits.…”