Dimensional Analysis of Horizontal Axis Wind Turbine Scaling Design

Observation of a small-scale wind turbine in a wind tunnel is a preliminary way to produce data that would describe the aerodynamic characteristics of the large one. The full-scale wind turbine has much greater Reynolds number than the miniature that makes the data might not be valuable directly. In this paper, the application of the Buckingham pi theorem is studied in predicting the performances of the full-scale wind turbine based on the small-scale wind turbine performances. The blade element momentum theory (BEMT) computation procedure is used to generate torque and thrust data of wind turbines that have diameters of 2.4 m, 10.0 m, 50.0 m, and 75.0 m. The generated data from the smallest rotor is prepared as small-scale wind turbine data. Based on the small-scale rotor data, the analysis produces equations expressing the correlation of rotor torque and thrust associated with diameters. Then, the powers of the wind turbines computed by BEMT are compared with the powers estimated by the dimensional analysis. The results show that the technique gives excellent accuracy. Therefore, it can be used confidently to assess the power measurement results of the large-scale rotor.