Analysis of Flap Side-Edge Flowfield for Identification and Modeling of Possible Noise Sources

The Reynolds Averaged Navier-Stokes (RANS) equations were solved for a wing with a half-span flap to simulate experiments performed in the NASA Ames 7x10 foot wind tunnel. The steady-state solutions were obtained using the CFL3D flow solver with various turbulence models and grids. Interrogation of the RANS computations revealed pertinent features of the flap side-edge flowfield. The extracted flow field features were used to guide the development of two possible noise-source models, namely, 1) a vortex-instability model and 2) a cylindrical vortex-sheet model. Both models predict flow unsteadiness (possible noise sources) in the relevant frequency ranges.