Upwind kinetic energy contributions to far wake meandering in wind turbines

The formation of wake meandering, a far wake large-scale oscillation, has been hypothesized to be due to disparate mechanisms: (1) large structures in the atmospheric boundary layer and (2) turbine bluff body effects. We identify energy contributions to wake meandering by quantifying the transfer from upwind scales. We employ large-eddy simulation and designate cases with different turbine blade parameterizations and upwind conditions to isolate specific upwind scales and interactions with wake meandering. The specific kinetic energy of a scale and interscale energy transfer is quantified through a methodology using triple and mode decomposition. Simulations with uniform inflow and the actuator surface model with and without nacelle model reveal different energy transfer behavior in the near wake due to the hub vortex. Subsequent neutral atmosphere boundary layer inflow conditions within a domain large enough to capture coherent structures are enforced on actuator disk and surface parameterizations. Several upwind scales are modulated by the wind turbine and shown to have significant effects on wake meandering.