Influence of Coriolis forces on wind turbine wakes in uniform inflow

As larger wind turbines are designed and manufactured, Coriolis forces become increasingly important to the deflection and distortion of turbine wakes in the atmospheric boundary layer. The deflection of turbine wakes impacts the power production of other turbines farther downstream in a wind farm. However, models for wind turbine wakes traditionally neglect or parameterize the effects of Coriolis forces. Large eddy simulations (LES) of an actuator disk model in barotropic, neutrally stratified, uniform inflow are performed over a range of Rossby numbers to vary the Coriolis forcing strength. Wake deflections scale with the inverse of the Rossby number, but lateral pressure gradients are non-negligible in the wake and counteract the Coriolis forcing to reduce wake deflection. To bypass modeling pressure fields for predicting the wake center, the absolute vorticity transport equation is instead used to model the lateral wake velocity. The transfer of planetary vorticity into streamwise and lateral vorticity components creates a counter-rotating vortex pair that induces a lateral velocity inside the wake and causes the wake to distort and curl. The physics presented here are incorporated into a new, physics-based wake model that is compared to LES results.