Vortex generators used to control laminar separation bubbles

This study examines the effect of various forms of vortex generators on the laminar separation bubble of a two-dimensional low Reynolds number Liebeck LA2573A airfoil. The objective of this research was to determine the effects that different generator sizes and spacings have upon the separation bubble and the drag. Windtunnel measurements were made on several generator configurations at Reynolds numbers ranging from 200,000 to 600,000 at angles of attack less than the stall angle where the separation bubble can provide a significant contribution to the airfoil drag. The vortex generators used were constructed small enough to be contained completely within the laminar boundary layer. Wind-tunnel data included airfoil drag and mean and fluctuating velocity measurements in the laminar and turbulent boundary layers. Results have shown that the use of vortex generators provides a measurable decrease in airfoil drag at the lower range of Reynolds numbers tested. At the airfoil's design condition and Reynolds number of 235,000, the submerged vortex generators were shown to decrease the airfoil drag by a maximum of 38% at C/ = 0.572.