Engineering blockage models

Among the engineering blockage models, some are used to derive an averaged efficiency that captures the negative impact of blockage-related flow perturbations on the annual energy production of a wind farm. DNV's BEET model belongs to that category.

Other models consist of a more detailed approach in which turbine-specific wind speed perturbations are estimated. The Rankine Half Body model [35] is a member of that category. It will likely be soon available in WindFarmer:Analyst.

Using CFD.ML for blockage predictions

It is noted, that CFD.ML inherently models blockage and wakes together, therefore the turbine interaction affected wind speeds coming out of CFD.ML will contain the impact of blockage (and wakes) on a per-turbine, per-flowcase basis.

That said, the CFD.ML results may be post-processed to obtain the annualized, farm-average blockage correction which can be used to correct engineering wake model results that don't capture the lateral and upstream flow features. When used in that context, CFD.ML may be seen as an alternative to the BEET.