The effects of boundary layer trips on airfoil flow fields at low Reynolds number

Boundary layer trip devices are commonly used to eliminate laminar separation bubbles on airfoils, but much of the focus has been at Reynolds numbers above Re = 100,000. Similarly, freestream turbulence has been shown to alter the flow field behavior around wings at very low Reynolds number (Re = 12,000). While the laminar-turbulent transition phenomena is key to boundary layer transition, drag reduction on airfoil, laminar separation bubble formation, and stall behavior, it remains unclear how a boundary layer trip might behave at very low Reynolds number. The current study will show computational and experimental results of a NACA 0012 airfoil at a Reynolds number of 12,000 with and without a boundary layer trip device. High order CFD will be compared with high speed, planar PIV measurements to determine whether or how the classical boundary layer trip performs the same task at very low Reynolds number. A comparison of these results with the impact of freestream turbulence effects will also be shown.