The image represents the results of a hybrid DNS/LES (by Zhiyin Yang and Peter Voke) computation of separation, transition and reattachment of the flow over a plate with a semicircular leading edge.

References:

1) Z. Y. Yang and P. R. Voke, "Large-Eddy Simulation of boundary layer separation and transition at a change of surface curvature using a dissipation-range subgrid scale model." J. Fluid Mech. 439, 305-333. 2001.

2) P. R. Voke, "Subgrid-scale modelling at low mesh Reynolds number," Theoret. Comput. Fluid Dynamics, 8, 131--143, 1996.