Novel experimental methods for investigating wind turbine rotor blade tip vortex formation and breakdown in atmospheric turbulence

• Applicant: Dr. Claudia Brunner
• Subject Area: Fluid Mechanics
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 569960847

Wind energy is a key technology for reaching ambitious international net-zero goals, and for the accurate planning and operation of wind energy projects, it is essential to model the atmospheric flow and its interaction with individual wind turbines and entire wind farms. One of the key aspects of understanding the physics of atmospheric flows and their interactions with wind turbines and wind farms as a whole is the formation and breakdown of tip vortices. Recent research has revealed the importance of the scales in the inflow turbulence on wind turbine and wind farm power output, and far wake development, But the effects of atmospheric turbulent conditions on (1) the aerodynamic forces acting near the rotor blade tip and the resulting tip vortex formation, (2) the subsequent tip vortex breakdown in the near wake and (3) the interactions and coupling effects between the tip vortex formation and its breakdown are not well understood. There is a need for field experiments which overcome the limitations of computational and laboratory-based studies. The aim of this proposal is therefore to develop novel experimental methods for studying combined effects of atmospheric turbulence on tip vortex formation and breakdown in the near wake of an operating wind turbine in the field. We do this by addressing the following objectives: (1) Develop a novel experimental method for studying the effect of atmospheric turbulence on blade aerodynamics near the tip; (2) Develop a novel experimental method for studying the effect of atmospheric turbulence on tip vortex dynamics; (3) Use the resulting data to determine relationships between inflow conditions, blade aerodynamics and vortex dynamics and (4) Publish unique open data sets to enable further research. The work involves adapting and scaling up existing experimental techniques from the two applicants, the Aerosense rotor blade surface measurement system from OST and the wind tunnel scale 3D Lagrangian particle tracking system from MPI-DS, to gain new scientific insights in the field. The unique combination of blade surface pressure measurements and 3D time-resolved flow visualisations implemented in this project will be used to relate blade aerodynamics to vortex dynamics. The published data sets of simultaneous blade pressure distribution and flow visualisation at high Reynolds numbers can be used for future validation of models and numerical simulations. Our improved scientific understanding of the effect of turbulence length scales on tip vortex formation and breakdown will advance the key area of atmospheric flow through wind farms.

• DFG Programme: Research Grants
• International Connection: Switzerland
• Cooperation Partner: Dr. Sarah Barber