Presentation Description: The interaction between wind turbine generator (WTG) induction zones within a wind farm, termed cumulative induction zone effect (CIZE, or Blockage Effect) has widely been accepted as a key and necessary consideration when assessing the wind resource and potential energy yield of a wind farm. CIZE modelling is not currently incorporated into industry standard software. Computational fluid dynamics (CFD) can calculate CIZE wind speed deficits for un-waked WTGs. However, attempts to calculate this for waked WTGs are problematic because the simultaneous effect of multiple wakes and multiple induction zones cannot be decoupled within CFD. Therefore, a separate approach must be considered. This presentation outlines an analytical approach for quantifying site specific CIZE. For each individual WTG within the array, the analytical CIZE method calculates the contribution from all other WTGs within the array based upon (i) the analytical induction zone model and the relative positions of the WTGs, and (ii) a method for calculating the cumulative sum/combination of induction zones. The analytical CIZE method is validated against CFD simulations by comparison of un-waked leading edge WTGs and CFD is benchmarked and validated against measured lidar data from an offshore wind farm. A range of wind farm arrays are assessed and wind farm characteristics impacting the magnitude of CIZE are presented and discussed.
Methodology: Presentation will include an overview of the study, discussion of key results, and interactive guess the CIZE game.