Exploring wind farms with alternating two- and three-bladed wind turbines

Laboratory experiments and numerical simulations were carried out to explore potential advantages of using alternating rows of 3-bladed and 2-bladed turbines within wind farms. The power output and turbulence around the units were compared with baseline wind farms composed of 3-bladed turbines. The experimental setups consisted of two arrays of aligned turbines with streamwise separation of five and ten rotor diameters d, sharing a spanwise spacing of 2.5d. Complementary Large Eddy Simulations at full-scale Reynolds number of Re≈10⁹ based on d were performed for the 5d setups. Results showed enhanced mean velocity and reduced turbulence levels in the heterogeneous wind farm as compared with the baseline in the 5d layout, which may imply lower dynamic loading; however, this was not reflected in the power fluctuation intensity. A marginal increase in the power of the 3-bladed turbines was offset by the diminished performance of the 2-bladed turbines. For the 10d cases, the benefits associated with the heterogeneous farm were negligible due to longer recovery distances. The performance of the heterogeneous wind farm did not improve over the baseline case; however, it may offer potentially lower costs of manufacturing and transportation, among others.