Detached Eddy Simulation (DES) of flap side-edge flow is performed with a NACA 632-215 wing and 30% chord, half-span flap configuration at a wing chord based Reynolds number of 3.7 million. This configuration has been used in previous experimental studies and Reynolds Averaged Navier-Stokes (RANS) simulations3'4 to understand the aerodynamic characteristics of the mean flap side-edge flow field. Aeroacoustic measurements5'8 have also been obtained for this configuration at a wing-chord Reynolds number of 1.7 million. In the present study, a RANS simulation is first performed as a precursor to the DES and the results are shown to closely match the experiments and the previous RANS study.3 The key unsteady features of the statistically stationary flap side-edge flowfield from the DES are presented. An instability of the rolled-up vortex near the leading edge of the flap side is identified to lead to the breakdown to turbulence of the side-edge flow field and is a potential key contributor to far-field noise.
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