Radiated Noise from Airfoils in Realistic Mean Flows

The long-term objective of the research described is to use computational aeroacoustics methodology and parallel computers to increase the understanding of broadband blade noise. In a systematic progression toward simulations of completely realistic configurations and conditions, some simplified problems that address the important features of the flow are investigated. A two dimensional Navier-Stokes code, implemented using the message passing library and Fortran 90 on the IBM SP2, is used to perform the calculations. Results are presented for the interaction of a vortical gust and NACA airfoils, including nonlinear effects. The influence of gust frequency and airfoil thickness is described. A multigrid method is used to obtain converged steady-state solutions before the gust is introduced in a source region inside the domain.