From turbine-scale to wind farm-scale wake recovery: Understanding the transition

Kasper, J. H.; Stevens, Richard J. A. M.

doi:10.1063/5.0285347

From turbine-scale to wind farm-scale wake recovery

J.H. Kasper and R.J.A.M. Stevens, Journal of Renewable and Sustainable Energy 18, 013302 (2026).

Featured article by the Journal of Renewable and Sustainable Energy. Open access and part of the ERC-funded WINDFLOW programme.

Main finding

Wind-turbine wakes and wind-farm wakes recover through different physical mechanisms. Behind a single turbine, recovery is dominated by spanwise turbulent transport. In the larger wind farms studied, vertical turbulent transport and the downward transport of energy by the mean flow dominate.

Energy-budget terms for simulated turbine and wind-farm wakes, showing spanwise turbulent transport dominating the isolated turbine and vertical terms dominating larger farms — **How to read the figure.** Each group is a simulated farm size, from 1 × 1 to 9 × 9 turbines. Panel (a) shows the integrated energy-budget terms; panel (b) compares their relative contributions. The dominant balance shifts from spanwise turbulent transport, T_y, behind the isolated turbine to vertical turbulent transport, T_z, and vertical mean-flow transport, M_z, behind the sampled farms with at least three rows and three columns. Open the full-resolution figure. Figure 10, cropped. J.H. Kasper and R.J.A.M. Stevens (2026), CC BY 4.0.

Why this matters

A wind-farm wake is not simply a wider version of a single-turbine wake. As the farm grows, recovery becomes increasingly coupled to transport from the atmosphere above the farm. This identifies vertical entrainment and downward mean flow as central processes for predicting recovery behind large wind farms.

Research context

The result comes from large-eddy simulations, in a deep conventionally neutral atmospheric boundary layer, of 25 staggered wind farms ranging from one turbine to a 9 × 9 array. It extends a research programme connecting multiscale wind-farm–atmosphere coupling, farm-to-farm wake interaction, and mesoscale representation of farm wakes.

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