Abstract: As wind-energy becomes an increasingly popular means to generate electricity, it is essential to develop a

more comprehensive understanding of the complex aerodynamics of wind plants. Wind-plant flows are complex because

they span a vast range of scales. The fuel to wind turbines is the wind of the atmospheric boundary layer. The depth of

the boundary layer can be up to a few kilometers (see figure 1) with the largest turbulent scales scaling with boundary

layer depth. The boundary layer is also forced by regional scale (mesoscale) weather phenomena with scales on the order

of tens or hundreds of kilometers. Each turbine develops a wake that interacts with other wakes and other turbines, and

wakes scale with the turbine rotor diameter. At the smallest scale, the turbine blades have their own boundary layers

with depths of millimeters to centimeters. Aside from the range of scales, atmospheric stratification plays an important

role in atmospheric boundary layer dynamics and hence the performance of the wind plant. Complex terrain and landsea

interactions further complicate the matter. In this presentation, I will focus on NREL’s large-eddy simulation efforts

in studying wind plant aerodynamics, but I will also show connections to lower-order modeling and applications like windplant

control and optimization. I will also touch upon the growing interdependence of experiments and simulation in wind

energy.

Bio: Matt Churchfield is a senior researcher at the National Renewable Energy Laboratory. He is part of NREL’s National

Wind Technology Center located just south of Boulder, Colorado. His research focuses on wind plant aerodynamics. He is

particularly interested in wind-turbine wake effects, mesoscale-microscale coupling, the effects of atmospheric stability on

plant behavior, and wind-plant control. Matt earned his masters and Ph.D. from Purdue’s School of Aeronautics and

Astronautics before joining NREL as a postdoc in 2009.