Modern wind turbine rotor blades are designed increasingly large and flexible. This structural flexibility represents a problem for the field of Computational Fluid Dynamics (CFD), which is used for accurate load calculations and detailed investigations of rotor aerodynamics. As the blade geometries within CFD simulations are considered stiff, the effect of blade deflections caused by aerodynamic loads cannot be captured by the “common” CFD approach.
To capture the effect of wind turbine blade deflections within CFD simulations, we implemented a new Finite Element solver into the CFD code OpenFOAM. Using an advanced beam element formulation based on the Geometrically Exact Beam Theory (GEBT), the structural model can capture geometric non-linearities such as large deformations. Coupled to RANS solvers of the OpenFOAM package, the new framework enables detailed investigations of flexible wind turbine blades.