Experiments on slat noise from −6° to 18° angles of attack

Abstract

© 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.This study focuses on investigating the slat noise of a two-dimensional scaled, unswept and untapered, MD30P30N high-lift model. The database refers aeroacoustic and aerodynamic measurements in a closed-section wind tunnel for a wide range of angles of attack, namely from −6° and 18°, and Mach number ranging from 0.07 to 0.1. Aeroacoustic measurements were carried using a wall-mounted microphone array. The signal processing applied to the acoustic data involved conventional beamforming enhanced by two deconvolution algorithms, DAMAS and CLEAN-SC. Suction-based wall boundary-layer control was applied to provide a more two dimensional flow over the model span. Chord-wise and span-wise static pressure measurements were performed. Slat noise spectra revel low-frequency tones, broadband noise and a single broad tone in the higher frequency range. The results show all slat noise components are strongly affected by wing angle of attack. The low-frequency tones vanish at lower negative wing angles of attack but reach their higher level at lower positive angles of attack. The tones level variation within a narrow range of angles of attack may be over 10 dB/Hz. Overall, the dominant part in the slat noise spectra reduces as the wing angle of attack increases, rendering higher frequency noise components potential contributors to the overall noise.

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