The effect of periodic unsteady flow on aerodynamics and heat transfer on a curved surface

Aerodynamic and heat transfer investigations were performed on a constant c urvature curved plate in a subsonic wind tunnel facility far various wake p assing frequencies under zero pressure gradient conditions. Steady and unst eady bolmdary layer transition measurements were taken on the concave surfa ce at different wake passing frequencies in which a rotating squirrel cage was rued to generate the unsteady wake flow The data were analyzed using ti me-averaged and ensemble averaged techniques to provide insight into the gr owth of the boundary layer and transition. Ensemble averaged turbulence int ensity contours in the temporal spatial domain showed that transition was i nduced for increasing wake passing frequency and structure. The local heat transfer coefficient distributions for the concave and convex surfaces were determined for each wake passing frequency using a liquid crystal heat tra nsfer measurement technique. Aerodynamic and heat transfer investigations s howed that higher wake passing frequencies caused earlier transition on the concave surface. Local Stanton numbers,were calculated on the concave surf ace and compared to Stanton numbers predicted using a boundary layer and he ar transfer calculation method. On the convex side, no effect of wake passi ng on hear transfer was observed, due to a separation bubble that induced t ransition.