Eulerian Pressure-Velocity/ Lagrangian Vorticity-Velocity Coupling Applied to Wake and Forces Calculation of Biofouled Tidal Turbines

Abstract

Marine tidal turbines are subject to the environment in which they are deployed. In the natural environment, they are gradually colonized by sessile species. These fouling organisms modify the flow around the blades and in the wake of the tidal turbine. Unfortunately, they also complicate the numerical study of such tidal turbines by preventing the use of usual methods such as the Blade Element Method or the Lifting Line Theory. In this context, we propose to use an alternative solution, which combines an Eulerian code to study the near field with a Lagrangian code for the wake. After a short presentation of each code, the coupling method is detailed, and applied to the case of a tidal turbine with its own vertical axis. First results are shown and compared to a full Eulerian simulation. Although the data transmission between both codes works well, discrepancies were found due to abnormal increase of energy in the Lagrangian area. A solution is proposed and explained.