LAUSR

The linear momentum theory is used to analyze the power-extraction capability of dual-rotor wind turbines with equal-size rotors. The rotors of a dual-rotor wind turbine are modeled as two separate actuator disks. The stream tube encompassing the front rotor is modeled as two (inner and outer) stream tubes, with the rear rotor being fully enclosed within the front rotor inner stream tube. No assumption is made on airflow pressure in between the rotors. The effect of the front and rear rotor interaction on the airflow within the inner stream tube is included in the analysis. With the results obtained, axial thrusts on front and rear rotors are determined and later used as input for computational fluid dynamics simulation to determine flow characteristics across the rotors. Based on the flow pattern between the rotors, the total power coefficient of a dual-rotor wind turbine is related to the rotor separation distance. A general solution for the dual-rotor wind turbine is developed, which shows that the lar...