COMPUTATIONAL AEROACOUSTIC ANALYSIS OF FLAP DEFLECTION AND CAMBER OF AN AIRFOIL

A number of fields involve the study of noise generated by airfoils. As restrictions on the noise generated by machines such as jet engines and turbines become more stringent, there is a need to understand the phenomenon of aeroacoustics. In order to increase the lift of a wing, external flaps and highly cambered main elements are often deployed. These elements can also affect the noise created by the wing. A computational aeroacoustic analysis was carried out using ANSYS Fluent in order to assess the impact of these on the turbulence and noise generated by an airfoil. Airfoils with NACA 0012, NACA 4412 and Eppler 423 as the main element were studied at flap deflections of 0 degrees, 15 degrees and 30 degrees. The SST k-omega turbulence model was used along with a broadband noise-based acoustic model solver. Values of turbulence intensity, surface acoustic power level and X and Y-direction self and shear noise were plotted along the surface of the airfoil, and a direct correlation between turbulence and surface acoustic power was observed. It was also observed that the acoustic power generated by the airfoil showed an increasing trend on the suction side, with increase in both camber and flap deflection. However, this was compensated for by a corresponding decrease on the pressure side. The self and shear noise were also shown to exhibit an increasing trend with camber and flap deflection, with the Y-directional sources dominating at higher flap deflections.