TRANSITIONAL FLOW STRUCTURE ON CLASSIC AND WAVY WINGS AT LOW REYNOLDS NUMBERS

The paper presents experimental results on the boundary-layer structure and laminar-turbulent transition on a wavy wing designed for unmanned air vehicles (UAVs). The study has been performed at the chord Reynolds number of the order of 10 5 to compare the wings with smooth and wavy surfaces at similar conditions. The flow past Z-15-25 airfoil was investigated with a particle-image velocimetry (PIV). The method made it possible to obtain a spatial pattern of velocity perturbations on the wing with wavy surface.