Flap/lead-lag computational investigations on NREL S809 airfoil

This paper aims at getting some insight into aeroelastic instabilities on NREL S809 airfoil. The study is based on the solution of the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations where turbulence is modelled using a two-equation SST k-ω model. Preliminary fluid flow computations are performed for a fixed airfoil set at various angles of attack. The results showed good agreement with experimental data found in the literature. Flow induced-vibrations on the airfoil are then investigated using a strong coupling fluid-structure interaction approach. The URANS equations are then defined in Arbitrary Lagrangian-Eulerian (ALE) coordinates. Simulations are carried out for flap/lead-lag free oscillations. All computations are performed in 2D domain in which the governing equations are solved considering an incompressible flow and a Reynolds number based on airfoil chord Re = 3.33 × 105 to Re = 2 × 106.