Wake-mixing strategies offer promising opportunities to increase
wind farm power production, but their impact on structural fatigue loading
remains insufficiently understood. This study evaluates the helix wake-mixing
method by jointly assessing power gains and fatigue loads at the wind-farm
scale. A steady-state helix wake model is coupled to a data-driven load surrogate
model. The surrogate model was trained on aeroelastic simulations using inflow
slices generated by large-eddy simulations and predicts damage equivalent
loads based on sector-averaged wind speed and turbulence intensity. The
coupled framework is first evaluated on a two-turbine array, considering varying
helix pitch amplitudes and wake overlap. The model captures the trends
observed when coupling the surrogate model to large-eddy simulation inflow,
showing increased fatigue loads on both upstream and downstream turbines.
The framework is subsequently applied to a 69-turbine offshore wind farm case
study. Farm-wide optimization of the helix method at below-rated wind speeds
yields an increase of up to 1.1 % in annual energy production, accompanied by
increased fatigue loading across all evaluated components. The largest
increases are observed for the pitch bearings, while tower base loads are less
affected.
Publication Date: 2026-06-15