Analysis and suppression research of high lift device noise based on large aeroacoustic wind tunnel test

The exterior noise of large aircrafts is an important aspect for the airworthiness certification. The high-lift device is one of the key noise sources for large aircrafts, thus the analysis and reduction of high-lift device noise is important and meaningful. Based on the 5.5m×4.0m Aeroacoustic Wind Tunnel and a half model for the aeroacoustic study of large scale aircrafts, the high-lift device noise properties were studied experimentally. First, the experimental platform, the test model, the test system and noise reduction design were introduced. Then, based on the experimental results, the noise characteristics of the high-lift devices were analyzed. The effects on the noise from the angle of attack and the wind speed were compared. The effects on the high-lift device noise from the noise reduction design on slat and flap were investigated. The results show that, the high-lift device noise has a broad frequency spectrum, with some peak frequency components. As the angle of attack is increased, the noise of the model is generally increased in the medium to high frequency range. With the wind speed increased, the noise is increased dramatically, and the frequency spectra keep a good similarity. The peak noise is suppressed by the noise reduction design.