|April 26, 2017
J. Energy Resour. Technol
, (2017); doi: 10.1115/1.4036541
Since it is important to prevent the wake produced by upstream wind turbines from interfering with downstream wind turbines, a method of deflecting such wakes is desired. In this paper, we present the coupled analysis results of a CFD simulation involving a three-bladed wind turbine with a yaw control system that utilizes rFlow3D CFD code, which was developed by JAXA, primarily for rotorcraft use. Herein, 3D, compressible, and unsteady Reynolds averaged Navier Stokes equation with a Spalart-Allmaras turbulence model is adopted as the governing equation. In the present study, we begin by carrying out wind turbine computations using various yaw angles while focusing on the resulting wake velocity distribution and aerodynamic loads, after which we discuss the influence of the yaw angle. Next, based on the wake velocity distribution results for each yaw angle, we move on to a wake interference avoidance simulation for downstream turbines that utilizes two prepared turbines. Through the present study, the following characteristics were confirmed. The results show wake deflection produced by adding yaw angle can provide a sufficient wake skew angle even in far-wake events. Furthermore, the yaw angle introduction accelerates the progression of vortex dissipation and brings about early velocity recovery in the wake region. Simultaneously, the introduction decreases the power generation amount of the yawed upstream turbine and increases the fatigue load of flapwise moment added to the blade root. In this paper, the details of flow field, fluctuation, and the yawed turbine performance characteristics will also be described.