Turbulent flow around circular arcs

The flow around a circular arc is governed by the effect of sharp leading edge and arc's curvature. There range incidences where leading-edge separation bubble (LESB) formed on convex side arc, reattached boundary layer separates further downstream. Akin to foils cylinders, for increasing values Reynolds number, turns from laminar turbulent resulting in step change forces, here termed force crisis. This phenomenon characterized experimentally an with camber-to-chord ratio 0.22 number 53 530 218 000. Forces are measured both towing tank water tunnel, particle image velocimetry undertaken tunnel. In stark contrast crisis associated laminar-to-turbulent transition layer, here, it found be suppressed relaminarization layer. fact, LESB always at tested conditions, occurs up combination critical angles attack numbers. angle varies linearly number. These results may contribute design thin cambered wings, sails, blades transitional such as wings micro aerial vehicles, swept subsonic flight, turbomachinery blades, sails autonomous sailing vessels.