Aerodynamic and aeroacoustic analysis of airfoils with a serrated trailing edge during flow acceleration

Abstract This study investigates the effect of an owl-inspired serrated trailing edge on a symmetric Joukowski airfoil with a 12% thickness during the initial acceleration phase. Large eddy simulations were performed at various Reynolds numbers ( Re = 100,000, 250,000, 400,000, and 500,000) at a Mach number of 0.25 and a 5° angle of attack. At a Reynolds number of 250,000, a detailed analysis reveals that adding serrations is advantageous for enhancing the airfoil’s boundary layer stability and reducing noise with only a minor compromise in aerodynamic efficiency that improves over time and at higher Reynolds numbers. Analysis of aerodynamic and aeroacoustic influence on the flow reveals that laminar separation bubble breakdown on the conventional trailing edge airfoil is triggered by trailing edge sound waves. On the other hand, the serrations promote an earlier transition of the turbulent boundary layer without forming a laminar separation bubble. Across higher Reynolds numbers, the serrated trailing edge’s benefits persist, with earlier noise generation and boundary layer transition benefiting the serrated trailing edge’s non-dimensional force in the y -direction. Overall, adding serrations improves boundary layer stability and reduces trailing edge noise during both the acceleration and post-acceleration phases. These findings underscore the potential of serrated trailing edges for various applications and motivate further optimization efforts.