Abstract
The objective of this research was to investigate the behavior of the vortex formed in a wing-body juncture in a water tunnel flow. The wing-body juncture was created by mounting a symmetrical airfoil with an elliptical leading edge normal to a flat plexiglass plate. For various airfoil angles of attack, the flow in the juncture was visualized with hydrogen bubbles and with fluorescein dye and the data was recorded on videotape and analyzed quantitatively using a video-based motion analysis system. The dynamic behavior of the juncture vortex system was observed over Reynolds numbers ranging from 2000 to 6000 based on airfoil thickness and the results compared with data at each angle of attack. The frequency behavior was observed to be directly correlated to Reynolds number, being divided into three distinct categories: Steady (non-oscillating), oscillating with engulfment or wrap-around, and shedding and dissipating. At non-zero angles of attack the shifts in behavior between the categories were seen to move to a lower flow velocity. It was theorized that the airfoil at incidence presented a greater effective thickness than the zero incidence case thereby increasing the effective Reynolds number even though the flow velocity was the same. A numerical correlation of this effect was sought but not found.
Trosper, Jeffrey Randall (1994). Effect of asymmetric axial strain on the behavior of the juncture vortex system. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1994 -THESIS -T8574.