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Updated: Aug 15, 2026

Experimental Investigation of the Flow Structure over a Delta Wing Via Flow Visualization Methods
Published on: April 23, 2018
Aeroacoustics of a wing encountering large-scale vortex gusts
Xiangtian Li1, Wangqiao Chen2, Puyuan Wang3
1Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region, People's Republic of China.
None:
Large-scale gusts in urban environments can reach magnitudes comparable to the flight speeds of low-altitude aircraft, altering the noise generation of lifting surfaces. In this work, a generic problem of a straight wing at zero angle of attack subjected to large-scale vortex gusts is studied in an anechoic wind tunnel, and the acoustic measurements and flow visualisation are conducted. The vortex gusts were generated by a pitching wing and characterized using time-resolved particle image velocimetry. The flow field results reveal that the gust ratio reaches 0.8, and the maximum integral length scale reaches 18 times the leading-edge radius. Acoustic measurements show spectral humps with a superposed tonal peak at relatively low frequencies, associated with gust-induced noise. Leading-edge noise mainly contributes to the gust-induced noise. Spectral proper orthogonal decomposition of the time-resolved flow field around the leading edge is used to analyse the tone-related noise source, indicating that various noise generation processes coexist during the interaction. An empirical broadband-noise prediction model for gust encounters at zero angle of attack is also proposed that accounts for velocity fluctuations near the leading edge.
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