Document Type : Research Article
Department of Aerospace Engineering, Amirkabir University of Technology, Tehran, Iran
Department of Mechanical Engineering, Polytechnic of Milan, Milan, Italy
In the era of rapid technological developments, the green aircraft and winglets of an airplane play a crucial role in reducing fuel consumption and its ensuing pollution. In this regard, the novelty of this paper is to focus on investigating the effect of the different geometrical parameters of winglets planforms on improving the aerodynamic performance of a wing with a supercritical airfoil (NACA 641412) at lower Reynolds numbers (take-off and landing phase). These investigations were conducted experimentally in a wind tunnel by force measurements through an external force balance. The aerodynamic coefficients of CL and CL/CD were obtained for the clean wing and nine various winglet planforms at a wide range of angles of attack from -4° to 20° and Reynolds numbers from Re=0.99×105 to Re=1.98×105. Furthermore, to get better insight into the physics of the flow, the numerical simulation of specific cases was carried out. According to the force measurement and vorticity magnitude results, among single winglets of W1, W2, W3, and W4, the W1 winglet with vertical height and linear side showed a better performance in all Reynolds numbers with a maximum lift increment of 26%; also, the W7 winglet planform represented the best performance as in double winglets with a maximum lift-to-drag ratio increment of 40%.