Tidal Power Plant Operation and its Effects on Large Vortex Structure Evolution

The sustainable large-scale extraction of tidal range energy remains an offshore engineering challenge motivated by efforts to decarbonise infrastructure and economy in several parts of the world.
Tidal power plant proposals are subject to rigorous scrutiny over their feasibility and environmental footprint. In particular, uncertainties over water quality and siltation have been identified as implications that need to be addressed as the industry develops. These processes are closely linked to changes in the hydrodynamics caused by the presence and operation of constituent hydraulic structures. In this study we explore the fate of large-scale vortices formed by water jets induced by the operation of sluice gates and turbines within these confined impoundments. A novel coastal ocean finite element model has been coupled with tidal power plant operation algorithms that can simulate the hydrodynamics associated with ebb-only, flood-only and two-way generation. Results demonstrate that there are pronounced patterns associated with each operation strategy which affect the lifespan and the vorticity strength of the recirculation zones formed. A tracking algorithm was employed that relied on the vorticity and circulation quantites to identify the trajectories of hydrodynamic structures that might in turn induce morphodynamics and water quality changes within the impounded areas.