🔹Title: Large wind farm power and variability: insightsfrom turbulent boundary layer fundamentals


🔹Speaker: Charles Meneveau (Johns Hopkins University)


🔹 Abstract: In this presentation we examine the question of wind energy power density andvariability from the viewpoint of basic turbulent boundary layer physics. Werestrict attention to near-neutral atmospheric conditions and consider the limit ofvery large wind farms on flat terrains or off-shore. We first review thegeneralization of the constant flux, logarithmic layer concept for application to thewind turbine array boundary layer. In this type of boundary layer two logarithmicregions arise, one above and another below the turbine height. We show howsuch generalized logarithmic velocity profiles (or Monin-Obukhov similarity) canbe used to enhance our understanding of wind power density. We also considerthe question of wind farm power fluctuation characteristics, specifically itsfrequency spectrum. We show how basic knowledge about spatio-temporalspectra in wall-bounded turbulence can be used under some simplifyingassumptions to develop a tractable model of wind farm frequency spectra thatcan take into account any turbine layouts (e.g., aligned or staggered). Whereneeded, we refer to results from Large Eddy Simulations using actuator-diskparameterizations of wind turbines, as well as from some wind tunnelexperiments.The work to be presented arose from the contributions of J. Bossuyt (KU Leuven,Belgium), M. Wilczek (now U. Bayreuth, Germany), R. Stevens (now Twente U, NL),M. Calaf (Utah), J. Meyers (Leuven, B), D. Gayme (JHU), C. Shapiro (now DOE) andG. Starke (now NREL).We are grateful to the US National Science Foundation for financial support.