Characteristics of separated vortices generated from the tip of a cape

"Separation vortices are generated at the tip of a cape exposed to a tidal current perpendicular to the major axis of the cape. The boundary layer thickness increases with, increasing distance along the cape. Vortices are generated when the flow separates at the tip of the cape. An upwelling is generated due to the spin down of this separated vortex. This study examines the generation period and the strength (circulation) of the separated vortex by means of hydraulic experiments. The experimental results show that the Strouhal number is constant and does not depend on the Reynolds number when the flow condition is higher than a Reynolds of 300. The formation process of separated vortices is visible by these experiments. The strength of the separated vortex is related to the vorticity at the separation point. This vorticity is governed by the headland length, the current velocity and the Strouhal number. A theorem is proposed to describe the boundary layer development along a cape in which the boundary layer thickness increase along the cape is proportional to the headland length. This theorem shows good agreement with the experimental data."