Optimal leading-edge deflection for flapping airfoil propulsion

The aerodynamics of oscillating airfoils are crucial to understanding subjects such as rotor dynamics and bio-inspired flows. Unsteady airfoils have been studied extensively, but there is an overall lack of knowledge regarding newer and more complex kinematics. The present paper builds upon our modified version of the NACA0012 by numerically comparing its way of flapping with the standard flapping that is common in the literature. The comparison is conducted parametrically at a Reynolds number of 104 for two nondimensional amplitudes. Then, using a gradient-based optimization method, we search for pitching amplitudes that maximize the propulsive power and efficiency for both flapping modes. Results indicate that the proposed flapping methodology is more promising than conventional flapping, with thrust increases up to approximately 40%. Furthermore, the proposed mechanism achieves maximum propulsive power with near-optimal efficiency, a common limitation of traditional flapping airfoils.

Automated summary

This paper investigates the aerodynamic characteristics of oscillating airfoils, comparing the performance of a modified version of the NACA0012 with the standard flapping method. By employing a gradient-based optimization method, the study identifies pitching amplitudes that maximize propulsive power and efficiency. The results indicate that the proposed flapping method shows more potential and achieves higher thrust, with near-optimal efficiency, compared to conventional methods.