Measurement and formation of three-dimensional stall cells on two-dimensional airfoils

Authors
Sivaneri, Victor
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Other Contributors
Amitay, Michael
Hicken, Jason
Sahni, Onkar
Issue Date
2014-12
Keywords
Aeronautical engineering
Degree
MS
Terms of Use
This electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.
Full Citation
Abstract
The present work aims to identify, quantify, and understand the physics by which three-dimensional stall cells are formed on two-dimensional airfoils, using oil flow visualization, load cells, and Stereoscopic Particle Image Velocimetry (SPIV). The oil flow visualizations were conducted on two-dimensional NACA 0015 and NACA 0009 airfoils, at angles of attack ranging from 14° to 20°, Reynolds numbers ranging from 1.70x105to 4.20x105, and aspect ratios of 4, 6.67, and 13.33. Load cell data was conducted on a NACA 0015 airfoil, at angles of attack ranging from 0° to 20°, Reynolds numbers ranging from 1.70x105 to 4.20x105, and an aspect ratio of 4. SPIV experiments were conducted on a on a stalled two-dimensional NACA-0015, pitched to 18° angle of attack, at four Reynolds numbers ranging from 1.70x105 to 4.20x105. Oil flow visualizations were used for both qualitatively identify the stall cells and to calculate the near-surface skin friction field. The results showed that, the angle of attack, Reynolds number, aspect ratio, and the airfoil shape and thickness had a pronounced effect on the formation of stall cells. In order to understand the formation of stall cells, the effect of adding a passive disturbance, a zig-zag tape that attached to the airfoil's surface, was explored. The results showed that under some conditions, adding either a two-dimensional or a localized disturbance could alter the shape of the separation and yield the formation of stall cells. In addition, wall-mounted load cells were used to measure the lift and drag on the airfoil, in the presence or absence of stall cells. Finally, the SPIV measurements correlated the flow field over the airfoil with the oil flow visualization on the surface.
Description
December 2014
School of Engineering
Department
Dept. of Mechanical, Aerospace, and Nuclear Engineering
Publisher
Rensselaer Polytechnic Institute, Troy, NY
Relationships
Rensselaer Theses and Dissertations Online Collection
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