Experimental investigation of the aerodynamic performance of rhamphorhynchus muensteri-inspired airfoil profiles at low Reynolds numbers

The aerodynamic characteristics of a low Reynolds number bio-inspired wing model were examined, drawing inspiration from the wing structure of the extinct pterosaur species *Rhamphorhynchus*, known for its exceptional flight capability and maneuverability. The three different derived airfoils were tested in a subsonic wind tunnel for different angles of attack and Reynolds numbers of 25,000, 50,000, and 75,000. Despite similar structures, slight differences in bio-inspired airfoils caused notable changes in aerodynamic forces. To identify laminar separation bubbles (LSB) on the wing surfaces, smoke wire and oil visualization techniques were employed, effectively mapping laminar and turbulent flow regions. Stall behavior at critical angles of attack was observed, with smoke images highlighting flow separation patterns unique to each airfoil. Additionally, MiniCTA probes recorded voltage fluctuations in turbulence, offering key data on LSB dynamics. This study compared the aerodynamic performance of bio-inspired airfoils with conventional NACA profiles. The comparison results reveal potential advantages of bio-inspired airfoils, particularly in terms of aerodynamic efficiency at low velocitys, offering valuable data that can be considered in design and optimization processes. Especially the geometric structure of PT01 and PT03 airfoils delays flow separation and the greater resistance of the boundary layer to adverse pressure gradient allows them to reach higher stall angles compared to NACA profiles. It is seen that it becomes suitable for low velocity applications by increasing maneuverability with increasing friction. These results suggest that PT-inspired designs can serve as a foundation for developing more efficient and controllable wings in future low-velocity aerodynamic applications.