We computed fluid motion under overtopping jets behind a vertical breakwater. The bellow animation shows evolution of vorticities and interactions between vortices behind the structure. Typical coalescence of the vortices as well as induced displacements of the vortices through the vortex interaction can be found in the results. They highly depend on scale of the jets.

Ref.
Watanabe, Y., Wang, Y., Saeki, Y., "Fluid motion with wave overtopping behind a breakwater", Proceedings of international conference coastal structures '99, 183 - 191 (1999).