FSI Simulation of two back-to-back wind turbines in atmospheric boundary layer flow

The paper presents aerodynamic and fluid-structure interaction (FSI) simulations of two back-to-back 5 MW horizontal-axis wind turbines (HAWTs) at full scale and with full geometrical complexity operating in a stably-stratified atmospheric boundary layer (ABL) flow. The numerical formulation for stratified incompressible flows is based on the ALE-VMS methodology, and is coupled to a Kirchhoff-Love thin-shell formulation employed to model the wind-turbine structure. A multi-domain method (MDM) is adopted for computational efficiency. In the simulations presented the wind turbines are positioned one behind the other at a distance of four rotor diameters, which results in a noticeable power production loss for the downstream turbine due to the wake velocity deficit of the upstream turbine. The importance of including FSI coupling in the modeling to better predict the unsteady aerodynamic loads acting on the wind-turbine blades is also highlighted.