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Justin Aholt
Missouri University of Science and Technology
Deptartment of Mechanical and Aerospace Engineering
Advisor: Dr. Fathi Finaish
Abstract
This work was a computational study of the effects of laminar separation bubbles on a 16 percent thick elliptical airfoil at an angle of attack of 10 degrees and Reynolds numbers ranging from 60,000 to 2 million. In this study, computational fluid dynamics (CFD) was employed in order characterize the effects of decreasing Reynolds numbers on the size of the bubble, its effect on the pressure coefficient plots for the airfoil, and its effect on the lift, drag and aerodynamic efficiency of the airfoil. It was found that the separation bubble first appears at Reynolds numbers of 600,000, and is only stable at Reynolds numbers greater than or equal to 60,000. At its largest, the bubble spans as much as 30 percent of the airfoil. This bubble is capable of generating a marginal boost in lift at Reynolds numbers around 200,000, but at a steep penalty in terms of drag. At Reynolds numbers below 200,000, the bubble appears to have an adverse effect on the natural pressure peak of the airfoil, which negates the bubble's positive effects. The bubble introduces a tremendous price in terms of drag, increasing it by as much as 150 percent. While the separation bubble produces a noticeable increase in lift, it does not produce any improvement in aerodynamic efficiency.
Justin Aholt from Krakow, MO, is currently a junior in the Department of Mechanical and Aerospace Engineering at the Missouri University of Science and Technology. After completing his Bachelor's Degree in Aerospace Engineering, he intends to pursue an advanced degree with a focus on aerodynamics.
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