Numerical Analysis of the Effetcs of Blended Split Winglets on Aerodynamic Performance of Aircraft

Abstract

Air flows with different pressures on the upper and lower surfaces of a wing meet at the wing tip and trailing edge owing to the finite dimensions of the aircraft wings. As a result, wing tip vortices are formed, which increase the induced drag and reduce the aerodynamic performance of the wing. In this study, inspired by bird wings, we aim to design a winglet that reduces wing-tip vortices using a biomimicry method. To verify the numerical method, the ONERA M6 wing, on which experimental and numerical studies were conducted by NASA, is used. The flow around the ONERA M6 wing is modeled using SOLIDWORKS software. The flow region around the wing, whose solid model is created, is divided into finite volumes using the ANSYS Fluent software. To verify the numerical model, a verification analysis is conducted on the pressure coefficient changes using experimental conditions in the literature. After the verification study, computations are performed at various angles of attack for the NACA 4412 winglet profile, which is added to the tip of the ONERA M6 wing at a sweep angle of 60° and different cant angles. The geometric configuration that provides the highest value for the aerodynamic performance parameter known as the lift coefficient to drag coefficient ratio (C_L/C_D) is determined. The results obtained from the study show that the highest C_L/C_D is obtained for the flow at 3.06° angle of attack and 15° cant angle winglet. Moreover, it is also calculated that the blended split winglet design, in which the upper winglet is designed to be longer with a 15° cant angle and the lower winglet to be shorter with a −30° cant angle, provides a 24.6% improvement in the C_L/C_D compared to the base wing.