Documentation | Nightly test dashboard
Kynema-UGF (formerly Nalu-Wind), wherein UGF stands for unstructured-grid fluid dynamics, is a generalized, unstructured-grid, massively parallel, incompressible-flow solver. The codebase was initiated in 2018 from NaluCFD, which was developed by Sandia National Laboratories. Kynema-UGF is being actively developed and maintained by a dedicated, multi-institutional team from National Laboratory of the Rockies and Sandia National Laboratories.
Kynema-UGF was originally called Nalu-Wind (as part of the ExaWind stack), but was renamed in 2026 in order to reflect its broader, general computational-fluid-dynamics (CFD) capabilities.
Kynema-UGF is developed as an open-source code with the following objectives:
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an open, well-documented implementation of the state-of-the-art computational models for modeling flow physics relevant to energy systems that are backed by a comprehensive verification and validation (V&V) process;
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be able to leverage the high-performance leadership-class computing facilities available at DOE national laboratories.
When disseminating technical work that includes Kynema-UGF simulations please reference the following citations:
The following contains the introduction of Nalu-Wind as part of the ExaWind suite:
Sprague, M. A., Ananthan, S., Vijayakumar, G., Robinson, M., "ExaWind: A multifidelity
modeling and simulation environment for wind energy", NAWEA/WindTech 2019 Conference,
Amherst, MA, 2019. https://iopscience.iop.org/article/10.1088/1742-6596/1452/1/012071/pdf
The following contains details for Kynema-UGF (formerly Nalu-Wind):
Sharma, A., M.J. Brazell, M.J., G. Vijayakumar, S. Ananthan, L. Cheung, N. deVelder,
M.T. Henry de Frahan, N. Matula, P. Mullowney, J. Rood, P. Sakievich, A. Almgren, P.S.
Crozier, and M.A. Sprague, 2024, ExaWind: Open-source CFD for hybrid-RANS/LES
geometry-resolved wind turbine simulations in atmospheric flows. Wind Energy, 27,
225-257. https://onlinelibrary.wiley.com/doi/full/10.1002/we.2886.
Documentation is available online at https://kynema.github.io/kynema-ugf/ and is split into the following sections:
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Theory manual: This section provides a detailed overview of the supported equation sets, the discretization and time-integration schemes, turbulence models available, etc.
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Verification manual: This section documents the results from verification studies of the spatial and temporal schemes available in Kynema-UGF.
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User manual: The user manual contains detailed instructions on building the code, along with the required third-party libraries (TPLs) and usage.
All documentation is maintained alongside the source code within the git repository and automatically deployed to a github-hosted website upon new commits.
Kynema-UGF is primarily built upon the packages provided by the Trilinos project, which in turn depends on several third-party libraries (MPI, HDF5, NetCDF, parallel NetCDF), and YAML-CPP. In addition, it has the following optional dependencies: hypre, TIOGA, and OpenFAST. Detailed build instructions are available in the user manual. We recommend using the Spack package manager to install Kynema-UGF on your system.
Kynema-UGF comes with a comprehensive unit test and regression test suite that
exercise almost all major components of the code. The main branch is
compiled and run through a regression test suite with different compilers
(GCC, LLVM/Clang, and
Intel) on Linux and MacOS
operating systems, against the latest versions of
Trilinos. Tests are performed both using
MPI on CPUs and GPU hardware configurations. The results of the nightly
testing are publicly available on CDash
dashboard.
To report issues or bugs please create a new issue on GitHub.
We welcome contributions from the community in form of bug fixes, feature enhancements, documentation updates, etc. All contributions are processed through pull-requests on GitHub. Please follow our contributing guidelines when submitting pull-requests.
To pass the formatting check, use this with a new version of clang-format:
find kynema_ugf.C unit_tests.C ./include ./src ./unit_tests \( -name "*.cpp" -o -name "*.H" -o -name "*.h" -o -name "*.C" \) -exec clang-format -i {} +
Kynema-UGF is licensed under BSD 3-clause license. Please see the LICENSE included in the source code repository for more details.
Kynema-UGF was originally developed with funding from Department of Energy's (DOE) Office of Science Exascale Computing Project (ECP) and Energy Efficiency and Renewable Energy (EERE) Wind Energy Technology Office (WETO). It is currently supported by the DOE Office of Critical Minerals and Energy Innovation (CMEI).
Please see authors file for a list of contributors to Kynema-UGF, formerly Nalu-Wind.