Low Reynolds numbers and high turbulence intensities are inherent in the flight of small unmanned aerial vehicles (UAVs). A significant aspect of this unsteady motion is the pitching component of the flow, as perceived by the UAV, and the inherent risk of flow separation. The leading-edge suction parameter (LESP) has been proposed in the literature as a separation criterion. This paper trials the LESP in the erratic high-pitch-rate flow of onset turbulence. Two airfoils, a NACA0012 and NACA4412, have been tested at a Reynolds number of 100,000 and in turbulence intensities from 1.3 to 15%, replicating small UAV flight conditions. It is seen that, although the peaks in the LESP can indicate vortex shedding, the LESP in itself is not a sufficient criterion. Notably, there is not a critical value corresponding to vortex activity. Furthermore, the LESP does show sensitivity to camber, which is primarily apparent through the angle of the leading-edge suction vector.
Leading-Edge Suction Parameter in Turbulent Flow at a Low Reynolds Number
AIAA Journal ; 60 , 2 ; 798-808
2021-09-13
11 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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