20 Numerical Investigation of Reynolds Number Effect on Airfoil Aerodynamic Performances

By using the NUMECA commercial software FINE∕TURBO, numerical study on the effect of Reynolds number on aerodynamic performance of wind turbine airfoil NREL S825 has been carried out under Reynolds numbers, 1×10⁶, 2×10⁶ and 3×10⁶. The computation results have been compared to the experimental data of loading coefficients and shown the same tendency as the experiment. Boundary layer data, including velocity profile, boundary layer displacement and momentum thicknesses, are analyzed in detail, based on the numerical results. The calculation results show that at the same angle of attack, with the increase of Reynolds number, the boundary layer becomes thinner, resulting in the separation point moving downward, the lift efficient increasing and the drag efficient reducing as well.