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NREL Releases Improved Controls-Oriented Wind Farm Modeling Tool

May 17, 2019

The National Renewable Energy Laboratory's (NREL's) wind plant performance optimization software framework, FLOw Redirection and Induction in Steady State (FLORIS), has been enhanced to provide greater usability and additional representation of flow physics to take into account new advances in the understanding of the aerodynamics of wake steering as it pertains to advanced wind farm control strategies.

The latest release of this open-source code includes the following advancements:

  • Curled wake modeling. FLORIS now enables users to model wake steering using counter-rotating vortices, which occur behind yawed turbines. The understanding of these structures will be essential in unlocking the full potential of wake steering. This capability captures the three-dimensional aspects of wake steering effects on the overall flow field that impact multiple turbines downstream and promotes the idea of flow control within a wind farm. The curl model, originally proposed by NREL researcher Tony Martínez in Wind Energy Science, is described further and compared with other models in a newly published paper by NREL's Christopher Bay.

  • Upgraded open-source code. NREL software engineers thoroughly overhauled the code so it can be easily used and improved. Modularity enables new features and wake models to be added quickly, and a redesigned interface gives researchers more control over simulations.

  • Tools package. Users can now easily use integrated tools such as wake-steering optimization, flow visualizations, simulation comparisons, annual energy production calculations, and more.

  • Extensive documentation. Each function of the code now includes its own documentation. This new in-code documentation has also been compiled into a website. In addition, a series of examples offer working demonstrations of what FLORIS can do and help new users learn the framework.

3D illustration of FLORIS simulation

This 3D illustration shows a FLORIS simulation of three turbines generated using the new curl wake model. Above the turbines is a single plane visualization featuring the in-plane vortex flows leading to the curled shape. Illustration by Paul Fleming, NREL

"We're very excited to share these improvements with the research community and hope the framework facilitates collaboration by providing people a common space to share ideas," said NREL Senior Engineer Paul Fleming, who leads the laboratory's wind farm control research. "The new curl model has the ability to model critical behaviors for more precisely capturing the value of wind farm controls. In addition, by providing clear, worked examples, we hope to reach a new user base of people who want to try out wind farm control." Fleming encourages people who are currently using FLORIS to download the new version and take advantage of these enhancements.

NREL researchers use FLORIS to analyze wind farm control theory and to design and analyze field validation campaigns. The FLORIS framework provides a computationally inexpensive, controls-oriented modeling tool of steady-state wake characteristics in a wind farm. FLORIS is used in the design and analysis of wind farm controllers and is central to NREL's research in wind farm controls. Available for download on github.com/nrel/floris, FLORIS has been in existence for several years and was co-developed by NREL and the Delft University of Technology.

If you'd like to receive periodic updates on FLORIS, or for more details on using or contributing to the FLORIS open-source framework please send an email to paul.fleming@nrel.gov.