Experimental investigation of slat noise attenuation with trailing edge bending deformation

Deformable Slat noise research activity experimental studies at the high-lift configuration. Experiments were conducted in D5 aeroacoustic wind tunnel at Beihang University. The experimental test section consists of DSM and acoustic panels which can both reduce the interference of the jet shear layer and better measure the acoustic characteristics of the high lift device. The data is gained by three far-field microphones. It was found that the noise of the slat after deformation is obviously reduced, the frequencies of the slat noises caused by deformation were obviously changed. Moreover, it was founded that when the deformation of slat causes the gap to be sealed which is equivalent to totally eliminating the slat noise source through acoustic data. At the same time, it has the lift loss that can be ignored at the operative test angles of attack caused by the deformation of slat. Aiming at the research of the noise reduction of the deformed slat, ongoing work includes hot-wire measurements also will be used to measure the velocity fields to understand the interference effect between the vortices in the shear layer.