Study of Turbulence Statistics in Large-Eddy Simulations of Ocean Current Turbine Environments

As ocean current turbines move from the design stage into production and installation, a better understanding of oceanic turbulent flows and localized loading is required by researchers and members of industry. Consideration of realistic ocean turbulence environments, in particular, is essential for obtaining accurate and reliable predictions of ocean turbine lifetime and performance. In this study, large eddy simulations (LES) are used to model the turbulent boundary layer in which an ocean current turbine operates. The LES model captures current driving due to winds, waves, and tides, thereby providing a high degree of physical realism. Inflow and boundary conditions are designed to represent conditions during an observational campaign at Admiralty Head in Puget Sound, and comparisons are made between the LES results and available observational measurements. Further statistical measures of the LES flow fields are outlined, including vertical profiles of Reynolds stresses, turbine loading, and two point correlations. The ability of the synthetic turbulence generator TurbSim to reproduce realistic ocean turbulence is qualitatively assessed through comparisons with LES results. Finally, preliminary simulation results are presented for an ocean current turbine represented by an actuator disk.