The wind industry relies on flow models to estimate wind turbine energy production. Flow models have many non-physical parameters that are not measurable, and model developers determine default values indirectly by calibrating them with large data sets. While the default parameters ensure accurate results on average, experienced users will tweak them for their specific wind farm. Therefore, case-by-case tweaking based on proxy measurements is a symptom of non-physical model parameters.

WAsP 12.7 contains an atmospheric stability model with non-physical parameters. As stability influences the vertical wind profile, it seems reasonable to tweak the stability parameters based on local wind speed measurements. However, as parameters such as the Roughness Length also affect the vertical wind profile, tweaking the stability parameters may compensate for errors caused by the Roughness Length.

Floors, Troen, and Peña (2023) describe a newly developed atmospheric stability model in WAsP 12.8. The new model is reformulated with physical parameters and validated for six European sites. Results show that going from defaults to site-specific stability parameters reduces the power density error from 5% to 3%.

Floors, Rogier, Ib Troen, and Alfredo Peña. 2023. “Using Observed and Modelled Heat Fluxes for Improved Extrapolation of Wind Distributions.” Boundary-Layer Meteorology 188 (1): 75–101. https://doi.org/10.1007/s10546-023-00803-3.