Additive manufacturing of surface riblets for aerodynamic optimization: From fabrication to flow visualization

This study investigates the integration of additive manufacturing (AM), specifically fused deposition modeling, in the fabrication of microscale riblet geometries aimed at enhancing aerodynamic performance. Riblet structures with varying orientations and dimensional parameters were initially produced as flat-plate samples to examine their influence on flow direction and behavior using TiO 2 -based surface oil visualization techniques. The most effective riblet configurations were subsequently applied to NACA0015 airfoil models to evaluate their aerodynamic performance in a controlled wind tunnel environment. Comprehensive experimental tests including force measurements and detailed flow visualizations revealed that riblet-enhanced surfaces can manipulate flow behavior, delay stall onset, increase the lift, and reduce drag under certain conditions. Among the tested geometries, the 45° riblet configuration demonstrated a notable improvement in lift generation, while the 60° model provided smoother stall characteristics. Furthermore, the 0° riblet orientation exhibited a 2° stall delay, suggesting enhanced flow attachment even at higher angles of attack. This work demonstrates the feasibility and practicality of using cost-effective, scalable AM techniques for advanced surface engineering in aerospace applications, offering an innovative path for passive flow control without the need for complex and time-consuming conventional manufacturing methods.