Flow-driven simulation on variation diameter of counter rotating wind turbines rotor

Wind turbines model in this paper developed from horizontal axis wind turbine propeller with single rotor (HAWT). This research aims to investigating the influence of front rotor diameter variation (D1) with rear rotor (D2) to the angular velocity optimal (ω) and tip speed ratio (TSR) on counter rotating wind turbines (CRWT). The method used transient 3D simulation with computational fluid dynamics (CFD) to perform the aerodynamics characteristic of rotor wind turbines. The counter rotating wind turbines (CRWT) is designed with front rotor diameter of 0.23 m and rear rotor diameter of 0.40 m. In this research, the wind velocity is 4.2 m/s and variation ratio between front rotor and rear rotor (D1/D2) are 0.65; 0.80; 1.20; 1.40; and 1.60 with axial distance (Z/D2) 0.20 m. The result of this research indicated that the variation diameter on front rotor influence the aerodynamics performance of counter rotating wind turbines