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Wind Turbines

OASIS couples with OpenFAST to simulate offshore wind turbines on floating or fixed-foundation platforms. The coupling handles structural loads, aerodynamics, and control through the FASTurbine wrapper.

Coupling Architecture

graph LR
    O[OASIS] -->|platform motion| F[OpenFAST]
    F -->|forces & inertia| O
    O -->|wave kinematics| F

OASIS provides platform kinematics (position, velocity, acceleration) to OpenFAST, which returns:

  • Tower-base forces and moments
  • Turbine inertia matrices (body, tower, turbine)
  • Rotor loads

Requirements

OpenFAST coupling requires:

  1. OpenFAST 3.0.0 compiled as a shared library
  2. Intel oneAPI Fortran compiler (for OpenFAST build)
  3. FASTurbine wrapper (included in OASIS, requires separate build)
  4. CMake flag: -DUSE_OPENFAST=ON

See Installation — Windows for build instructions.

Configuration

Wind turbine definitions are provided in dataWindTurbines.dat. Each turbine is attached to a body and references an OpenFAST input file.

Time Steps

Two dedicated time steps control the coupling:

Parameter Description
fastTimeStep OpenFAST structural time step (in dataProblem.dat)
fastControllerTimeStep OpenFAST controller time step (in dataProblem.dat)

These can differ from the OASIS hydrodynamic time step to match OpenFAST's requirements.

Output Files

File Format
FASTurbW_<ID>_bodyInerMat.dat 6×6 body inertia matrix (Armadillo ASCII)
FASTurbW_<ID>_towrInerMat.dat Tower inertia matrix
FASTurbW_<ID>_turbInerMat.dat Turbine inertia matrix
WindTurbineForce_Body_<ID>.txt Time + wind turbine forces on body
Example Feature
turbines/fixed_turbine Turbine on fixed-foundation body
turbines/moored_turbine Turbine on moored floating platform