Experimental and numerical study of wing boundary layer behavior in propeller flowfield

In this research, the effects of propeller slipstream on wing boundary layer and transition front were studied through wind tunnel tests and numerical analysis. In this respect, the flow around a NACA 6-series airfoil section was simulated in a computational fluid dynamics solver without and with propeller flowfield. The numerical study, presented in this paper, was concerned with the effect of propeller slipstream on both wing aerodynamics and boundary layer treatment. For experimental tests, oil flow visualization technique was used to determine laminar to turbulent transition location, laminar separation bubble with turbulent reattachment and turbulent separation line over the wing surfaces. Existence of propeller slipstream changed pressure and skin friction distribution over the wing surfaces, in both chordwise and spanwise directions and it hence affected on the wing loading distribution. Also upstream propeller affected on boundary layer characteristics including laminar/turbulent transition onset and separation over the wing. The results showed that the transition location moved toward the leading edge, and the separation bubble was washed out due to propeller slipstream.