Tonal noise generation in blunt trailing edges

Abstract

The present work concerns the investigation of airfoil noise generated by the unsteady flow past an airfoil and its subsequent propagation to the far-field. This study is of paramount importance for the design of aerodynamic configurations such as wings and high-lift devices, as well as gas turbine blades and wind turbine blades, fans, propellers and automotive cross-bars. In this project, we will investigate the tonal noise that arises from vortex shedding generated by blunt trailing edges. The unsteady aerodynamic flows analyzed give rise to physical phenomena at a broad range of energetic scales. Therefore, Direct Numerical Simulation (DNS) is the numerical method of choice for the flow simulations since it captures all the energetic scales associated with both noise generation and propagation. The acoustic predictions will be performed by DNS and the Ffowcs Williams-Hawkings (FWH) acoustic analogy formulation. The surface and volume integrations of dipole and quadrupole source terms appearing in the FWH equation will be performed in order to evaluate the effects of trailing edge bluntness on the individual noise sources. Numerical simulations will be conducted for a NACA0012 airfoil with different blunt trailing edges for several Mach numbers. Thus, compressibility effects on tonal noise will be investigated. An aerodynamic and aeroacoustic analysis of suction and blowing effects on blunt trailing edges will be presented. (AU)