Characterisation of boundary layer transition over a low Reynolds number rotor

An experimental investigation on the flow topology over a rotor operating at low Reynolds numbers is presented. The feasibility of laminar to turbulent transition experiments small rotors demonstrated. Phase-locked infrared thermography coupled with simultaneous force and torque measurements were used study three bladed NACA0012 aerofoil section set uniform angle incidence 10°. Boundary layer was forced using two-dimensional (2D) three-dimensional (3D) roughness elements, placed approximately 5% 28% blades chord. In 3D configurations once critical attained streaks downstream developed into fully wedges. For current configuration, it found that state boundary can significantly affect its performance, non-optimal forcing generally resulting in loss performance when compared smooth reference case.