Experimental Aeroacoustic and Aerodynamic Analysis of a Large-scale Flap Side-edge Model

In this research, the relationship between the parameters of a large-scale flap model and the physics responsible for flap side-edge noise generation, one of the most dominant sources of the airframe noise was investigated by performing experimental tests in a wind-tunnel. Flow field measurements conducted with a multi-hole pitot probe located behind the flap tip were complemented by phased microphone array techniques to increase the understanding of flap side-edge noise sources and their correlations to unsteady vorticity fluctuations. Conventional beamforming and CLEAN-SC and DAMAS methodologies were used to obtain far-field acoustic spectra estimations and noise source mapping. The model used for the tests consists of an unswept isolated flap element with representative tip details presented in a medium range transport aircraft. The model instrumentation includes 106 steady pressure taps distributed chord-wise and span-wise and a trip tape that eliminates laminar boundary layer effects. Noise reduction devices were also assessed and compared to the baseline configuration regarding noise reduction. Aerodynamic and aeroacoustic tests were conducted in the LAE-1 closed circuit wind tunnel at the São Carlos School of Engineering - University of São Paulo (EESC-USP) in flow speeds up to 38 m/s. The results provided specific information about the aeroacoustic and aerodynamic characterization of the flap model dominant acoustic source mechanisms.