Date of Award

Spring 2023

Embargo Period


Access Type

Thesis - Open Access

Degree Name

Master of Aerospace Engineering


Aerospace Engineering

Committee Chair

Ebenezer Gnanamanickam

First Committee Member

Anastasios S. Lyrintzis

Second Committee Member

Richard Prazenica

College Dean

James W. Gregory


Bio-inspired wing tip devices were investigated with the goal of improving the fuel efficiency of subsonic aircraft. Particularly, the structure of a bio-inspired winglet design based on bird feathers were tested in a low-speed wind tunnel. Particle image velocimetry (PIV), was used to study the flow field at two planes aft of the wing as the wing tip vortices developed downstream. These were time-dependent, stereoscopic particle image velocimetry (sPIV) measurements carried out at two planes located at 0.7 and 2 chord distances downstream from the wing. The structure of the wingtip vortices was compared and contrasted with that formed over a wing without a wing tip device and that over a conventional winglet such as that seen in general aviation. In addition, the aerodynamic characteristics obtained using force balance measurements (as part of a previous study) were analyzed to determine an approximation for the induced drag. The wing with the bio-inspired winglet generated the highest lift at a given angle of attack, as reported previously. At higher angles of attack, the wing with the conventional winglet had the minimum induced drag. All three wing configurations generated significant vortical motion at the wing tip. The wing with no attachment and the wing with the conventional winglet showed the distinct signature of a vortex. The mean velocity, mean vorticity and turbulence intensity fields collectively presented strong evidence that the wing without an attachment had a larger vortex core at both downstream locations considered, when compared to the wing with the conventional winglet. However, in contrast, the wing with the bio-inspired wing tip device showed no clear vortex core at both downstream locations. Instead, pockets of vorticity were observed. These pockets appeared to organize itself into a larger vortex at the downstream location. In addition, the wing with the bio-inspired winglet also appeared to have a larger more diffused vortical structure when compared to the other configurations.

Available for download on Thursday, May 01, 2025