Video of a cross section of a flow over a CVG on a flat plate, at low speeds 60m/sec. This shows turbulent flow over the front of the section, to the lower left, and a restructuring of the flow as it crosses the CVG into a series of coherent vortices that are stabilised by the upper boundary layer interaction. The vortices are effectively trapped in the sub boundary layer which is now hybrid. This image shows extended persistence of the structure.