Effect of leading-edge roughness on boundary layer transition of an oscillating airfoil

A series of experiments were conducted to study the effect of leading-edge roughness onthe state of the boundary layer of a wind turbine blade section using multiple hot-film sensors. theexperiments involved static and dynamic tests, where airfoil motion was of plunging type oscillation. theapplication of surface grit roughness simulates surface irregularities that occur on the wind turbine blades.the measurements showed that increasing the angle of attack results in movement of transitionlocations toward the leading edge. surface roughness moved the transition point toward the leading edgeand caused early trailing edge turbulent separation, which resulted in reducing the effectiveness of theairfoil. boundary layer instability frequencies were dominated through the transition.