Boundary layer forcing on a rotating wing at low Reynolds numbers

Two separate experiments were conducted on a three-bladed NACA0012 rotor operating at a blade tip Reynolds number ranging from 44 − 110 × 10 3 using phase-locked infrared thermography (IRT) coupled with force and torque measurements. The first experiment consisted of a parametric study on the impact of forcing boundary layer transition using roughness placed on the suction side of the aerofoil in a hover configuration. Boundary layer forcing on a rotating wing at low Reynolds numbers with earlier transition, where the excrescence drag due the roughness elements would not be present in the freestream turbulence forcing case.