Flow Separation around Airfoil and Aerodynamics Forces at Low Reynolds Numbers

Abstract

Aerodynamic forces on the NACA0012 aerofoil were measured and a flow visualization around it by smoke was made in a low Reynolds number region. Lift and drag force measurements were made using an external strain gage balance for a chord Reynolds numbers range of 2.0×(10)^4∿1.3×(10)^5. A flow visualization study at Re=1.3×(10)^4 was performed and correlated with the force measurements. We found that there were two patterns of vortex shedding : one was concerned with a trailing vortex winding up from the lower surface around the trailing edge in the region below 6 degree. The other was caused by Kelvin-Helmholtz instability in the region greater than 11 degree.