Wind shear and veer cut actuator-disk turbine power coefficient by more than 20 percent via geometric and inductive mechanisms

Concurrent-precursor LES runs across veered and sheared inflows isolated geometric effects from rotor-equivalent wind speed changes and inductive effects that modify thrust and wake induction. Controlled cases holding shear magnitude fixed while varying veer demonstrated an adverse pressure gradient at rotor scale that lowers the power coefficient independently of speed variation. These inductive losses grow linearly with veer angle and are amplified by wall proximity, processes omitted from blade-element momentum codes used for site assessment.

Field campaigns cited in the paper recorded up to 15 percent efficiency swings; the simulations exceed that range because they resolve rotor-scale pressure fields absent from nacelle anemometer data. The decomposition shows inductive shear effects act through spanwise induction gradients while veer effects act through streamwise pressure forcing, allowing separate parametrization rather than lumped empirical corrections.

Engineering models that ignore these terms will over-predict annual energy production in veered nocturnal jets common at hub heights above 100 m. Next steps require embedding the reported induction adjustments into farm-scale codes and testing against lidar-inflow turbine power data to quantify bill impacts within two years.