Presets
Playback
Wind and wake
Wake decay constant k is about 0.04 offshore and 0.075 onshore.
Farm layout
Spacing in rotor diameters D = 126 m.
Layers
Model checks
The science
Actuator disc and Betz
A rotor with thrust coefficient Ct = 4a(1 - a) slows the flow by the axial induction a, and extracts Cp = 4a(1 - a)2, at most 16/27 at a = 1/3. Power is P = ½ ρ A Cp η U3 up to the rated 5 MW, zero below 3 m/s.
Jensen / Park wake
Behind a rotor the wake is a cone of radius Rw = R + k x with uniform deficit δ = (1 - √(1 - Ct)) / (1 + 2kx/D)2. This keeps the mass-flux deficit δ π Rw2 constant. Several wakes combine by root-sum-square; a turbine's inflow is the disc average, so a partly overlapped rotor loses less.
Honest simplifications: top-hat engineering model (no turbulence, shear, yaw steering, or terrain); the edge of the colour map is smoothed for display only; a generic 126 m, 5 MW-class turbine; power curve is idealised; no Weibull wind statistics.
What to try
- Increase row spacing from 4 D to 10 D and read the farm efficiency graph.
- Turn the wind 25 degrees: wakes miss the next row.
- Compare k = 0.04 and 0.075 in the recovery graph.