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OpenFAST and FAST.Farm#

OpenFAST is a multi-physics, multi-fidelity tool for simulating the coupled dynamic response of wind turbines. Practically speaking, OpenFAST is the framework (or “glue code”) that couples computational modules for aerodynamics, hydrodynamics for offshore structures, control and electrical system (servo) dynamics, and structural dynamics to enable coupled nonlinear aero-hydro-servo-elastic simulation in the time domain. OpenFAST enables the analysis of a range of wind turbine configurations, including two- or three-blade horizontal-axis rotor, pitch or stall regulation, rigid or teetering hub, upwind or downwind rotor, and lattice or tubular tower. The wind turbine can be modeled on land or offshore on fixed-bottom or floating substructures.

FAST.Farm is a midfidelity multiphysics engineering tool for predicting the power performance and structural loads of wind turbines within a wind farm. FAST.Farm uses OpenFAST to solve the aero-hydro-servo-elastic dynamics of each individual turbine, but considers additional physics for wind farm-wide ambient wind in the atmospheric boundary layer; a wind-farm super controller; and wake deficits, advection, deflection, meandering, and merging. FAST.Farm is based on some of the principles of the dynamic wake meandering (DWM) model—including passive tracer modeling of wake meandering—but addresses many of the limitations of previous DWM implementations. FAST.Farm maintains low computational cost to support the often highly iterative and probabilistic design process.

Building OpenFAST and FAST.Farm#

In this section we provide cmake scripts for installation of OpenFAST and FAST.Farm. Both tools can be installed by following the instructions here.

FAST.Farm is installed as a cmake option to the build of OpenFAST.

You can clone your desired verstion of OpenFAST from here. Once cloned, cd into the OpenFAST directory and create a build directory. Use the scripts given below from within the build directory to build OpenFAST and FAST.Farm. On a Kestrel CPU node, build OpenFAST by executing the following script from within the build directory:

Sample job script: Building OpenFAST and FAST.Farm using cmake on CPUs 
#!/bin/bash

module purge
module load PrgEnv-intel/8.5.0
module load intel-oneapi-mkl/2024.0.0-intel
module load intel-oneapi
module load binutils
module load hdf5/1.14.3-intel-oneapi-mpi-intel

module list

cmake .. \
    -DCMAKE_Fortran_COMPILER=ifx \
    -DCMAKE_CXX_COMPILER=icpx \
    -DCMAKE_C_COMPILER=icx \
    -DCMAKE_CXX_FLAGS=-fPIC \
    -DCMAKE_C_FLAGS=-fPIC \
    -DBUILD_OPENFAST_CPP_API=ON \
    -DBUILD_FASTFARM=ON \
    -DDOUBLE_PRECISION:BOOL=ON \
    -DCMAKE_BUILD_TYPE=Release \
    -DOPENMP=ON \
    -DCMAKE_INSTALL_PREFIX:PATH=${PWD}/install

nice make -j48
make install

Note

The option OPENFAST_CPP_API needs to be enabled if further coupling to AMR-Wind is desired. Otherwise, the user can set the option to OFF.

Note

OpenFAST is not GPU-ready.

Running OpenFAST#

OpenFAST is a serial tool and can be executed by simply calling it directly

Sample job script: Running OpenFAST on a dedicated node 
    #!/bin/bash

    #SBATCH --account=<user-account> # Replace with your HPC account
    #SBATCH --time=01:00:00
    #SBATCH –-nodes=1
    #SBATCH --partition=shared

    module purge
    module load PrgEnv-intel/8.5.0
    module load intel-oneapi-mkl/2024.0.0-intel
    module load intel-oneapi
    module load binutils
    module load hdf5/1.14.3-intel-oneapi-mpi-intel

    openfast <your_turbine_input_file>.fst

Examples of turbine models are available in the regression tests repository, here.

Note

OpenFAST input files change from one version to another. If you build a certain version, ensure your input files (or exemples from the regression tests repository linked above) are compatible with your version.

Running FAST.Farm#

FAST.Farm is OpenMP-capable, but still runs within a node. Its execution is similar to OpenFAST.

Sample job script: Running FAST.Farm on a dedicated node 
    #!/bin/bash

    #SBATCH --account=<user-account> # Replace with your HPC account
    #SBATCH --time=01:00:00
    #SBATCH –-nodes=1

    module purge
    module load PrgEnv-intel/8.5.0
    module load intel-oneapi-mkl/2024.0.0-intel
    module load intel-oneapi
    module load binutils
    module load hdf5/1.14.3-intel-oneapi-mpi-intel

    FAST.Farm <your_fastfarm_input_file>.fstf

FAST.Farm input deck can become complex depending on your simulation model. FAST.Farm users are encouraged to use accompanying toolbox for case setup available here.