Experimental Investigation of Wake Characteristics in Aligned and Staggered Wind Turbines

Wake interactions between wind turbines have a significant impact on the performance of downstream turbines and the overall efficiency of wind farms. In this study, wind tunnel experiments were carried out to investigate the wake characteristics of multiple wind turbines under different inflow conditions, upstream yaw angles, and turbine arrangements. The applicability of a previously proposed blade optimization method for reduced-scale wind turbine wake experiments was further assessed, and several wake velocity superposition models were evaluated. The results indicate that inflow turbulence intensity has a greater influence on wake recovery than inflow velocity and that increased turbulence intensity accelerates wake mixing and velocity recovery. Moreover, an appropriate upstream yaw angle and a staggered turbine arrangement can alleviate the wake deficit experienced by the downstream turbine. Additionally, the experimental data confirm that the optimized blade design method is effective for multi-turbine wake experiments. Among the models considered, the geometric sum model shows the best agreement with the experimental data under non-yaw conditions with small turbine spacing. The present study provides useful reference data for wind farm layout optimization and wake model development.