MS#04.3 Active Wake Mixing

G. YALLA¹, K. BROWN¹, J. GUTKNECHT², J. FREDERIK³
¹ Sandia National Laboratories|² TU Delft|³ National Renewable Energy Laboratory

Turbine technology and Control

Overview
The mini symposium on Active Wake Mixing (AWM) at the Wind Energy Science Conference (WESC) aims to bring together researchers and industry experts to explore the latest advancements and challenges in the field of wake mixing for wind farms. As the demand for renewable energy continues to rise, optimizing wind farm performance through innovative wake management strategies has become increasingly critical. This symposium will focus specifically on the emerging technology of wake mixing based control strategies, and serve as a platform for sharing research ideas, fostering collaboration, and discussing practical applications and current limitations of AWM technologies.

To mitigate power losses associated with wake interactions between turbines, several wind farm control strategies have been proposed including turbine derating, wake steering, and wake mixing. The focus of this mini symposium is on the latter, in which the turbine is used as a flow actuator to excite wake instabilities that will accelerate wake recovery. A common strategy is to introduce periodic oscillations in the blade-pitch through the turbine controller to excite turbulent structures at specified frequencies and wavenumbers that will entrain momentum into the wake.

Although AWM has shown promising results in recent studies, it remains a nascent field with several challenges to address, including the development of strategies to reduce turbine loads while maintaining power benefits. Additionally, new opportunities are emerging for floating offshore turbines, which provide greater flexibility in implementing active controls due to the increased degrees of freedom. Furthermore, farm-level active control strategies are emerging as an effective mean to mitigate cluster wakes that impact farm-to-farm interactions. Overcoming these challenges and embracing these new opportunities will depend on advancements in control optimization, a deeper understanding of the fluid dynamics involved in AWM, and improved reduced-order modeling techniques, all of which will be the focus of this mini-symposium.

The symposium will cover a range of topics related to active wake mixing including but not limited to:

• Modeling and Simulation: Techniques for accurately modeling wind farm wake interactions and the impact of AWM strategies on overall performance.
• Control Algorithms: Development and implementation of advanced control algorithms for optimizing turbine operation in the presence of wake effects through wake mixing.
• Experimental Validation: Case studies and experimental results demonstrating the effectiveness of AWM strategies.
• Fluid Dynamics Analysis: Analyzing the fluid mechanics underlying AWM to explain wake dynamics and performance between strategies.
• Impact on Energy Production: Assessing the potential benefits of AWM on energy yield and overall wind farm performance, particularly deep array effects.