Prof. Charles Meneveau
Louis M. Sardella Professor, Department of Mechanical Engineering, Johns Hopkins University
Turbulence and Reduced Models for Large Wind Farms
Monday, March 18, 2019, 12:00pm to 1:00pm | Room 5-314
In this presentation we discuss several properties of the flow structure and turbulence in the wind turbine array boundary layer (WTABL). This particular type of shear flow develops when the atmospheric boundary layer interacts with an array of large wind turbines. Based on such understanding, we aim to develop reduced order, analytically tractable models. These are important engineering tools for wind energy, both for design and control purposes. After reviewing some basic tools to predict mean velocities for total power optimization, we will focus on two fluid mechanical themes relevant to wind farm control and inherent variability. We describe a simple (deterministic) dynamic wake model, its use for wind farm control, and its extensions to the case of yawed wind turbines based on a re-interpretation of lifting line theory adapted to the problem of yawed actuator disks. The second part deals with spectral characteristics of the fluctuations in power generated by an array of wind turbines in a wind farm. We show that modeling of the spatio-temporal structure of canonical turbulent boundary layers coupled with variants of the Kraichnan's random sweeping hypothesis can be used to develop analytical predictions of the frequency spectrum of power fluctuations of wind farms. The work to be presented arose from collaborations with Juliaan Bossuyt, Johan Meyers, Richard Stevens, Tony Martinez, Michael Wilczek, Carl Shapiro and Dennice Gayme. We are grateful for National Science Foundation financial support.