Characterizing the Coherent Structures Within and Above Large Wind Farms

Zhang, M.; Stevens, R.J.A.M.

doi:10.1007/s10546-019-00468-x

Publication 74 · Wind-farm flow

Characterizing the Coherent Structures Within and Above Large Wind Farms

M. Zhang, R.J.A.M. Stevens, Bound.-Layer Meteorol 174, 61-80 (2020).

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Main finding

Large coherent structures extend through and above simulated wind farms, while turbine wakes dominate correlations at turbine-passage frequencies. The modal analysis does not prove that a few modes control farm power or enable flow control.

Proper orthogonal decomposition modes at hub height and in the vertical plane — **How to read the figure.** Streamwise velocity of several proper orthogonal decomposition modes at hub height in a periodic aligned wind farm (a), with the streamwise, spanwise and vertical components of the first mode in a vertical cross-section between turbine rows (b). The first mode is a set of full-length streamwise bands spanning the whole domain, so the organised structures run through the farm rather than being confined to individual wakes. This is structural evidence for the simulated cases, not proof that a few modes control farm power. Open the full-resolution figure. Figure 6. M. Zhang and R.J.A.M. Stevens (2020). No separate licence is stated here; consult the original publication and credited source before reuse.

Why this matters

Large coherent structures extend through and above wind farms, while turbine wakes dominate correlations at turbine-passage frequencies.

Research context

Builds on Characterizing the coherent structures in large eddy simulations of… (read the finding), Flow Structure and Turbulence in Wind Farms (read the finding), and cited POD studies. Extended by A three-dimensional dynamic mode decomposition analysis of wind farm… (read the finding) through DMD selection/reconstruction and related later coherence/control work.

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