Solar enhanced soaring: Tapping into ambient solar energy for optimized airfoil performance

Abstract

The amount of solar and background radiation absorbed by birds varies according to their wing shape, pigmentation, porosity, etc. Birds are equipped with unique features to thrive, including attracting the opposite sex, regulating body temperatures, and soaring in the sky. The research focuses on solar/sky radiation 146by examining how the NACA0012 airfoil, representing the wing of a bird, performs when its upper surface temperature is higher or lower than the surrounding ambient air. This is realized by performing 2-dimensional simulations in OpenFOAM at a Reynolds number of 33,000, where the Spalart-Allmaras model is used to simulate the flow turbulence. The upper surface of the airfoil is warmed to 330 K and cooled to 270 K at a pressure of 1 atm, an ambient temperature of 300 K, and a Mach number of 0.0725. The results illustrate the airfoil with the cooler top surface exhibits a lower drag and higher lift than its warmer top surface counterpart. A maximum reduction of drag coefficient from 0.065 to 0.061 and an increase in lift coefficient from 0.89 to 0.93 at an angle of attack of 11° are achieved. In short, tuning the upper surface of the NACA0012 airfoil to temperatures lower than the ambient provides better aerodynamic performance. © 2024 Jenny Stanford Publishing Pte. Ltd. All rights reserved.