A Comparative Design Study of Biomimetic Multiwinglets for Tip Vortex Splitting

Abstract Biomimetic designs draw inspiration from biological organisms for engineering design. This paper presents a design and analysis of multiple-piece winglets based on the wingtip feathers of birds. The biomimetic multiwinglet designs proposed in this work have the potential to improve aerodynamic performance. The hypothesis was that the designs cause splitting of the standard large single-tip vortices into multiple, smaller tip vortices. This separation into smaller vortices has the potential to reduce induced effects. The proposed biomimetic multipiece winglets have the following design parameters: number of winglets, individual winglet dimensions, dihedral angles, angles of attack, and sweep angles. The simulations were performed using a reduced-order potential flow method on the program open vehicle sketch pad (openvsp)/vspaero, known as vortex lattice method (VLM), but modified in the program. These modified VLM simulations were used to calculate values like lift, total drag, and induced drag of the various designs, which were tabulated to establish the efficacy of each design parameter. Various combinations of these parameters were studied to find the optimal designs. The simulation data is provided for this comparative design study, which includes the effects on the variation of chordwise positions and dihedrals of the winglets. The current findings indicate that the most effective parameter is likely the gap distance between the winglets. Based on the current findings, a planform gap distance near or equivalent to the local winglet chord lengths contributes to optimal performance.