MS#02.2 Modeling atmospheric boundary layer impacts on wind power from rotors to wind farm wakes

M. HOWLAND¹, S. PORCHETTA²
¹ Massachusetts Institute of Technology|² TU Delft

Wind farms and wakes

There is an urgent need to inform the siting, design, and control of wind farms being deployed to meet net-zero targets. To expand energy production, wind turbines are rapidly increasing in rotor diameter and hub-height. Meanwhile, wind farms are proliferating to new locations and are increasing in both size and siting density. As a consequence of these growth trends, wind turbines are accessing new regions of the atmospheric boundary layer (ABL) that older, smaller wind turbines have not operated within. Bigger wind farms are stimulating large-scale interactions with the atmosphere.  This mini-symposium will present research innovations that improve our fundamental understanding and fast-running models of the impacts of shear, stability, and Coriolis effects in the stratified ABL on wind power systems.

Historically, wind turbines have operated entirely in the surface layer, which is the lowest ~10% of the ABL where the log-wind profile is valid. Given the rapidly growing size of modern wind turbines, they are either partially or completely operating above the ABL surface layer, experiencing new and more complex wind shear, stratification, and turbulence than older, smaller turbines. Increasingly, wind turbines and wakes are affected by wind speed shear, wind direction shear (veer), low level jets, and Coriolis effects. Further, a key assumption within ABL surface layer theory is that the dynamics are not influenced by the boundary layer depth. This assumption increasingly breaks down in the analysis and modeling of larger turbines and wind farms that are influenced by the height of the ABL, the strength of the capping inversion, and the free atmosphere stratification. These ABL mechanisms of wind shear, stability, and Coriolis effects will impact the power production and loads of individual wind turbines, the wakes generated by wind turbines, the blockage and entrainment of kinetic energy in wind farms, and the large-scale wakes generated by wind farms.

This mini-symposium will present novel investigations of the interactions between the ABL and wind power systems. Contributed talks will focus on the impacts of ABL phenomena and processes including but not limited to wind shear, stability, and Coriolis effects on wind turbine rotor aerodynamics, wind turbine wakes, and wind farm level dynamics including blockage and kinetic energy entrainment, and farm wakes. The presentations may focus on improved fundamental understanding using computational fluid dynamics, laboratory experiments, and field experiments and/or improved engineering modeling. The goal of this mini-symposium is to further integrate the wind power aerodynamics and boundary layer meteorology communities to unlock innovations in modeling renewable wind power production.