Aerodynamic optimization design of low reynolds number aerofoils based on induced laminar separation

Abstract

At low Reynolds numbers, the design of aerofoils with a high lift-to-drag ratio (RLD) is crucial for enhancing the aerodynamic performance of Micro Air Vehicles (MAVs). However, the transition from laminar to turbulent flow plays a dominant role in the aerodynamic performance of aerofoils at Low-Reynolds-Numbers (LRN). The laminar separation bubbles formed in laminar flow alter the effective aerofoil shape, reducing aerodynamic efficiency. Additionally, predicting the shape and location of the laminar separation bubbles becomes challenging due to its sensitivity to the flight environment. To design aerofoils suitable for low Reynolds number MAV applications, we optimize a high RLD aerofoil by inducing transition to improve the effective aerofoil shape in the flow field. The study reveals that excessive curvature can suppress the formation of laminar separation bubbles at the leading edge, redirecting separation to the midsection. This results in reduced aerofoil drag and enables a high lift distribution at the leading edge.