Modeling the Effects of Surface Waves on Power Generation of Cross-Flow Turbines

Cross-flow turbines are distinct from the more common axial flow turbines, as they extract energy from moving water with the axis of rotation perpendicular to the freestream velocity. Previous research utilizes a steady uniform freestream velocity to understand performance, but many turbines are installed in locations where free surface effects may be important. To understand these effects, we develop a computational fluid dynamics model combining steady uniform freestream flow and surface wave conditions in which we place a two bladed turbine horizontally in the channel. We conduct simulations with and without the presence of waves under various operating conditions and wave parameters. We report turbine performance and unsteady forces on the blades, which are also compared with experimental data and baseline turbine simulations. This framework is then extended to multiple turbine and surface wave configurations. This research will be able to explore the effects of deep- vs shallow-water waves, turbine distance from the free surface, and other setup parameters on power generation. The results will help inform cross-flow turbine installation to maximize power generation in channels with surface waves.