Physics understanding and control of boundary layer separation employing surface microstructures

Abstract

This study delves into the efficacy of trailing edge surface microstructures (TESM) in mitigating boundary layer separation on a National Advisory Committee for Aeronautics 0015 airfoil to augment aerodynamic performance. Three-dimensional quasi-spherical structures were integrated onto the upper surface of the airfoil near the trailing edge. The large eddy simulation approach was employed to solve the flow at a Reynolds number of 600 000 and an angle of attack of 17°. Key findings underscore notable disparities in vortex formation and turbulent flow evolution between clean and TESM airfoils, underscoring TESM's capacity to impede turbulent spot formation. Particularly, airfoils outfitted with TESM showcased diminished pressure oscillations over the surface compared to clean airfoil and prevented the formation of large eddies and upward flow movement, resulting in enhanced aerodynamic efficiency. Consequently, there was a 7% augmentation in lift coefficient, a 53% reduction in drag coefficient, and a remarkable 120% increase in lift-to-drag ratio observed. As an intriguing discovery, employing the TESM airfoil leads to an average reduction of 75% in the amplitude of lift and drag oscillations.