Richard J.A.M. Stevens

Physics of Fluids · University of Twente

Publication 42 · Wind-farm flow

Dependence of optimal wind-turbine spacing on wind-farm length

R.J.A.M. Stevens, Wind Energy 19 (4), 651-663 (2016).

Main finding

The diagnosed IBL height is defined by recovery of vertical kinetic-energy flux to 99% of inflow, constrained above the rotor, and fitted with coefficient near 1/3 and a maximum near 850 m. The model agrees best with staggered LES because horizontal averaging cannot encode row-to-row placement; agreement with operating-farm directional data is indicative, not decisive validation.

Optimal turbine spacing against cost parameter and number of rows
How to read the figure. Optimal geometric-mean turbine spacing as a contour map against the cost parameter and the number of turbine rows in the farm. The optimum moves to wider spacing as the farm gets longer: in a longer farm each turbine draws on a boundary layer that upstream rows have already depleted. The objective here is cost minimisation, so the optimum is defined only relative to that objective and its cost parameters. Open the full-resolution figure. Figure 7. R.J.A.M. Stevens (2016). No separate licence is stated here; consult the original publication and credited source before reuse.

Why this matters

Supports “optimal spacing increases with farm length under the stated objective.”.

Research context

Longer farms place more weight on fully developed momentum replenishment and therefore favor lower turbine density; shorter farms exploit high entrance production. This is a conditional reduced-model result, not a general design prescription.

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