Control of Artificially-Generated Hairpin Vortices in a Laminar Boundary Layer

Experiments were conducted to investigate the use of coherent vortical structures for boundary layer re-energization in a laminar boundary layer. The structures were generated artificially in the form of a hairpin train using a synthetic jet actuator to ensure repeatability for assessing the control. The structures act as a proxy for naturally occurring large-scale motions found in turbulent boundary layers. The hairpin train was controlled by both a static pin and a jet-assisted surface-mounted actuator (JASMA), and the results were captured using particle image velocimetry (PIV). Planar PIV was used to run a parameter study on several actuator strengths, angles, and heights along the domain mid-plane. Stereoscopic PIV measurements conducted downstream were aggregated into a volume of data for further analysis of the control of one particular hairpin train generation case. It was found that both the passive control pin and the active control JASMA contribute turbulent kinetic energy and downwash downstream to increase mixing and momentum injection into the boundary layer.

Year
2024
Publication Date
Published In
AIAA SciTech
Authors
Wylie, J., Amitay, M.
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