CFD Simulations of Two Wind Turbines Operating in Line

In this study, we perform CFD simulations for the NTNU Blind Test 2 experiment, in which two turbines were placed in a closed-loop wind tunnel and operating in line. The Reynolds-averaged Navier Stokes (RANS) equations with the k-w SST turbulence model are adopted in the simulations. For each of the two wind turbines, geometries including the blades, hub, nacelle, and tower are fully resolved. The Moving-Grid-Formulation (MVG) approach with a sliding interface technique is leveraged to handle the relative motion between the rotating and stationary portions of the wind turbines. In the simulations, the values of tip-speed ratio (TSR) for the upstream and downstream turbines are 4 and 6, respectively. The CFD-predicted thrust and power coefficients are obtained under an inlet velocity of 10 m/s and are compared against the experiment results. In addition, the wake structures of the two wind turbines are also visualized and discussed.