A Lattice Boltzmann Method for Horizontal Axis Wind Turbine Simulation

Operating horizontal axis wind turbines (HAWT) generate large-scale wake structures that can have considerable impact on downwind turbines. A HAWT exposed to vortices from upwind turbines generally produces reduced power and experiences increased structural vibrations that cause disproportionally accelerated material fatigue. Numerical simulation of the turbulent flow field is a viable approach to improve the understanding of vortex-turbine interactions and to optimize the control and layout of a wind farm. HAWTs are commonly represented with actuator disc or line models in array simulations due to the difficulties of solving the incompressible or weakly-compressible Navier-Stokes equations on moving three-dimensional meshes effectively, cf. [21]. As an alternative to the presently employed methods, we have developed a novel parallel adaptive lattice Boltzmann method for large eddy simulation of turbulent weakly compressible flows with embedded moving structures. Power and thrust coefficients are predicted within 5% of manufacturer’s specifications [28]. Wake velocity and pressure deficits along with their fluctuations are scrutinized in the near wake region of a Vestas V27 turbine revealing the three dimensional interactions induced by tower and ground vortex sheets. Simulations of the U.S. Department of Energy’s Scaled Wind Farm Technology facility show the influence of an upwind turbine’s tower on its wake extends to the down wind turbine. These results confirm that the approach is capable of simulating realistic operation of Vestas 27 turbines including tower and ground interaction accurately for moderate computational cost.