Active Vortex Generator Deployed on Demand by Active Hybrid Composites From Shape Memory Alloys and Fiber Reinforced Polymers

High performance airfoils with laminar airflow exhibit minimum drag and maximum lift, but tend to sudden stall due to flow separation at low air speed. This requires an increased approach speed of the aircraft, resulting in less steep approaches and a higher noise exposure of the surroundings. New active vortex generators, deployed only on demand at low speed, energizing the boundary layer of air flow and reducing flow separation, can help to overcome this critical situation. Active hybrid composites, combining the actuation capability of shape memory alloys (SMA) with the possibility of tailoring the compliance of fiber reinforced polymers (FRP) on the materials level, provide an active aerodynamic system with high lightweight potential and small space requirements. Being one of the first applications of active hybrid structures from SMA and FRP we will demonstrate the potential of this new technology with an integrated system of active vortex generators for a glider. In this contribution we present - the design process, based on a FE-model and careful characterization of the actuating SMA and the composite material - manufacturing relevant aspects for reliable series production - the testing of single vortex generators in lab scale under aerodynamic load - and an overview of the whole system.