Aeroelastic load analysis of a co‐rotating quad‐rotor wind turbine

Abstract

AbstractAn aeroelastic analysis is carried out to assess the loads on a selected quad‐rotor wind turbine vis‐à‐vis those on an equivalent rated single‐rotor turbine, with a specific focus on a comparison of support structure loads (e.g., tower root, yaw‐bearing, and boom loads). A quad‐rotor wind turbine with combined rated power of 6 MW and a single‐rotor with equivalent machine rating are modeled in SIMAPCK coupled with AerodynV15 (including turbulent wind input from TurbSim) to calculate the aerodynamic loads. A correction for tower/boom shadow is implemented in Matlab to account for reduction in (axial) incoming wind due to the presence of support structures that carry the rotors. The performance of the quad‐rotor wind turbine, with the single‐rotor as baseline, is carried out for load cases selected from wind turbine certification standard (IEC‐61400‐1) covering the following: nominal loads under normal wind speed profile, fatigue loads under normal turbulence, and ultimate loads under extreme turbulence. Results show that, comparing the quad‐rotor tower root loads to those of the single‐rotor turbine under extreme turbulence, the side‐side force is up to 31% higher, the force‐aft bending moment is up to 15% higher, and the normal force is up to 46% higher due to additional boom/nacelle inertial loads.