Fluid Structure Interaction of Wind Turbine Airfoils

Abstract

Flow induced vibrations of two airfoils used in wind turbine blades are investigated by a strong coupled fluid structure interaction approach. The method is based on a general Computational Fluid Dynamics (CFD) code that solves the Navier-Stokes equations defined in Arbitrary Lagrangian Eulerian (ALE) coordinates by a finite volume method. A straightforward technique is implemented in a user subroutine for the coupling of the CFD code to a structural dynamics program to determine the airfoil displacements due to the aerodynamics forces and for updating the grid at each time step. Simulations are carried out for a free pitch oscillating airfoil and for a combined pitch and vertical oscillating airfoil. Beforehand, the problem of the flow around a forced pitch oscillating airfoil is considered to check the reliability of the moving mesh technique and the CFD computations. All computations are performed in 2D, incompressible and low Reynolds number flows.