Richard J.A.M. Stevens

Professor at the University of Twente

Wind energy · Turbulence · Environmental flows

Publication 123 · Wind-energy acoustics

How wind-farm layout changes modeled noise

J. Colas, A. Emmanuelli, D. Dragna, and R.J.A.M. Stevens, Renewable Energy 273, 126052 (2026).

Read the article Open-access version

The article and Figure 14 are open access under CC BY 4.0.

Main finding

In one modeled stable-atmosphere case, a staggered 4 × 4 wind farm produced spatially averaged downwind sound levels about 3 dBA higher than the aligned layout beyond 2 km. The coupled calculation attributes the difference to both layout-dependent turbine source emission and sound propagation through the wind-farm flow.

Spatially averaged modeled overall sound pressure level and amplitude modulation versus downstream distance for aligned and staggered four-by-four wind farms, with the staggered case about 3 dBA higher beyond 2 km
How to read the figure. Panel (a) shows the modeled overall sound pressure level, averaged across receivers within |y| < 720 m, versus downstream distance. The gray band and dotted lines mark the wind-farm rows. Beyond 2 km, the staggered layout (blue) remains about 3 dBA above the aligned layout (black). Panel (b) shows the corresponding amplitude modulation; near 2.5 km its sampled maximum is about 2 dBA for the staggered layout and 1 dBA for the aligned layout. The curves compare one modeled stable case and are not a general layout law. Open the full-resolution figure. Figure 14, cropped. J. Colas, A. Emmanuelli, D. Dragna, and R.J.A.M. Stevens (2026), CC BY 4.0.

Why this matters

Wind-farm noise is not obtained by multiplying an isolated-turbine prediction. Layout changes the wake velocity and turbulence encountered by each rotor, which changes the modeled source emission. The combined wind-farm wake also changes atmospheric refraction and focusing between the turbines and receivers. Both parts of the source-to-receiver chain therefore have to be represented when layouts are compared.

Research context

The comparison couples actuator-disk large-eddy simulation, turbulent-inflow and trailing-edge source models, and wide-angle N × 2D parabolic-equation propagation. It covers aligned and staggered 4 × 4 farms of NREL 5 MW turbines at 4D streamwise and spanwise spacing, one stable atmospheric boundary layer, one ground model, and frequencies from 50 to 1080 Hz. A model-bookkeeping comparison assigns about 1.5 dBA of the downwind layout difference to turbine source powers and the remainder to propagation, but this is not an uncertainty-bounded causal decomposition. The calculation has no fully three-dimensional acoustic benchmark, displayed source-height or angular convergence, flow ensemble, field validation, or human-response evidence. It therefore does not establish a universal staggered-layout penalty, a worst atmospheric condition, or a permitting or annoyance outcome.

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