3D Numerical Study of the Impact of Macro-Roughnesses on a Tidal Turbine, on Its Performance and Hydrodynamic Wake

Biofouling is an important factor to consider when calculating the energetic efficiency of tidal farms. Despite fact that biofouling effects have been widely investigated in past for naval applications, very few studies concern turbines. This paper proposes a numerical approach assess impact on turbines, which efficient testing many configurations. Two turbulence models are tested (RANS k-ω SST and LES Smagorinsky) motionless blade case validate them. Then we chose use Smagorinsky model complete turbine rotor with realistically fouled blades. The pressure coefficient strongly affected by barnacle power slightly degraded case. Motionless cases do not represent real behaviour two reasons. First, sessile species settle down flow part chord where their less important. Then, surrounding provoked blades rotation reduces biofouling. In wake, generates small vortexes propagate into larger ones, causing them spread energy.