Computation of trailing-edge noise at low Mach number using largeeddy simulation

The present work is a continuation of the work described in the previous annual research briefs (Wang 1996, 1997). The objectives of the project are twofold: (1) to develop numerical prediction methods for trailing-edge noise, using a combination of large-eddy simulation (LES) and Lighthill’s theory; and (2) to generate a reliable numerical database for the study of noise source mechanisms. Trailing-edge aeroacoustics is of importance in both aeronautical and naval ap-plications. It is, for example, related to airframe noise, rotor and propeller noise, and noise from underwater vehicles. When turbulent boundary layer eddies are convected past the trailing edge of a large (relative to acoustic wavelength) body, their aeroacoustic source characteristics are modied by the edge, and a more e-cient source results (Ffowcs Williams & Hall 1970; Crighton & Leppington 1971). This scattering mechanism produces strong, broadband radiation to the far-eld. If there is coherent vortex shedding, typically associated with blunt trailing edges and/or high angles of attack, tonal or narrowband noise is also present. In addi-tion, the highly unsteady edge flow may cause low frequency vibration of an elasti