Combined analytical/FEA-based coupled aero structure simulation of a wind turbine with bend-twist adaptive blades

The simulation of wind turbines with bend-twist adaptive blades is a coupled aero-structure (CAS) procedure. The blade twist due to elastic coupling is a required parameter for wind turbine performance evaluation and can be predicted through a finite element (FE) structural analyser. FEA-based codes are far too slow to be useful in the aerodynamic design/optimisation of a blade. This paper presents a combined analytical/FEA-based method for CAS simulation of wind turbines utilising bend-twist adaptive blades. This method of simulation employs the induced twist distribution and the flap bending at the hub of the blade predicted through a FEA-based CAS simulation at a reference wind turbine run condition to determine the wind turbine performance at other wind turbine run conditions. This reduces the computational time significantly and makes the aerodynamic design/optimisation of bend-twist adaptive blades practical. Comparison of the results of a case study which applies both combined analytical/FEA-based and FEA-based CAS simulation shows that when using the combined method the required computational time for generating a power curve reduces to less than 5%, while the relative difference between the predicted powers by two methods is only about 1%. (c) 2006 Elsevier Ltd. All rights reserved.