Scale-resolving simulations of atmosphere / wind farm interactions

Offshore wind energy is seeing huge growth thanks to a steady reduction in the cost of power generation and it is now acknowledged that it will be critical for the 2050 net zero target. A large proportion of cost reduction is derived from using very large turbines. Further efficiency gains are expected from even larger rotors, but efficient design and operation of such colossal wind turbines poses some fundamental engineering challenges. Current design rules for turbine separation and operation (which scale with the rotor diameter) will need to be revisited, which calls for a better understanding of the dynamic interactions between different atmospheric conditions, the moving and deforming rotors, and their wakes. Such investigation needs to be performed through computer simulation, using models that resolve both the turbulent atmospheric conditions at farm scale, and their local dynamic effects at the rotor level. On a recent EPSRC/NERC funded project, we have built such simulation framework (1) and demonstrated its suitability to farm scale simulations on very large computing architectures.
Wake steering is the controlled misalignment of the turbines with the incoming flow to modify the impact on their wakes on downstream turbines. It has been shown in small scale farms (2) that this cooperative strategy can have a beneficial overall advantage in power production, but much is still unknown in terms of both wake physics, their dependency with atmospheric conditions (e.g., humidity and temperature) and their interactions with rotors, for the adoption of such promising technology in new wind farm developments. This will be addressed in this project, which will carry out a systematic investigation of the independencies between atmospheric conditions, rotor yawing strategies, and the expected power output and dynamic loading on the blades. This information will inform blade/gearbox fatigue models to assess potential trade-offs between power output gains and reduction of operational life.
The project has been defined as a CASE PhD studentship with SSE Renewables as an industrial partner. SSE Renewables will host the student and participate in the definition of the problem and the assessment of the results. The collaboration with SSE Renewables for this project will allow us to investigate various rotor yawing strategies under different atmospheric conditions for large-scale wind farms managed by SSE Renewables.