Effects of Concave Curvature on Boundary Layer Transition Under High Freestream Turbulence Conditions

An experimental investigation has been carried out on a transitional boundary layer subject to high initially 9 freestream turbulence, strong acceleration K vU2w xdUwdx as high as 9 x 10-6, and strong concave curvature boundary layer thickness between 2 and 5 of the wall radius of curvature. Mean and fluctuating velocity as well as turbulent shear stress are documented and compared to results from equivalent cases on a flat wall and a wall with milder concave curvature. The data show that curvature does have a significant effect, moving the transition location upstream, increasing turbulent transport, and causing skin friction to rise by as much as 40. Conditional sampling results are presented which show that the curvature effect is present in both the turbulent and nonturbulent zones of the transitional flow.