Active flap control on an aeroelastic wind turbine airfoil in gust conditions using both a CFD and an engineering model

In the past year, smart rotor technology has been studied significantly as solution to the ever growing turbines. Aeroservoelastic tools are used to asses and predict the behavior of rotors using trailing edge devices like flaps. In this paper an unsteady aerodynamic model (Beddoes-Leishman type) and an CFD model (URANS) are used to analyze the aeroservoelastic response of a 2D three degree of freedom rigid body wind turbine airfoil with a deforming trailing edge flap encountering deterministic gusts. Both uncontrolled and controlled simulations are used to asses the differences between the two models for 2D aerservoelastic simulations. Results show an increase in the difference between models for the y component if the deforming trailing edge flap is used as control device. Observed flap deflections are significantly larger in the URANS model in certain cases, while the same controller is used. The pitch angle and moment shows large differences in the uncontrolled case, which become smaller, but remain significant when the controller is applied. Both models show similar reductions in vertical displacement, with a penalty of a significant increase in pitch angle deflections.

[1]  Niels N. Sørensen,et al.  Investigation of the load reduction potential of two trailing edge flap controls using CFD , 2011 .

[2]  J. Gordon Leishman,et al.  Unsteady lift of a flapped airfoil by indicial concepts , 1994 .

[3]  Hrvoje Jasak,et al.  Error analysis and estimation for the finite volume method with applications to fluid flows , 1996 .

[4]  T. Theodorsen.  General Theory of Aerodynamic Instability and the Mechanism of Flutter , 1934 .

[5]  Leonardo Bergami,et al.  ATEFlap Aerodynamic Model, a dynamic stall model including the effects of trailing edge flap deflection , 2012 .

[6]  Mac Gaunaa,et al.  Unsteady two‐dimensional potential‐flow model for thin variable geometry airfoils , 2010 .

[7]  Christian Bak,et al.  A dynamic stall model for airfoils with deformable trailing edges , 2009 .

[8]  James D. Baeder,et al.  Direct Calculation of Three-Dimensional Indicial Lift Response Using Computational Fluid Dynamics , 1997 .

[9]  Niels Kjølstad Poulsen,et al.  Advanced Load Alleviation for Wind Turbines using Adaptive Trailing Edge Flaps: Sensoring and Control , 2010 .

[10]  K W McAlister,et al.  Application of the ONERA Model of Dynamic Stall , 1984 .

[11]  Jens Nørkær Sørensen,et al.  The Science of Making Torque from Wind 2014 (TORQUE 2014) , 2014 .

[12]  A. Gosman,et al.  Solution of the implicitly discretised reacting flow equations by operator-splitting , 1986 .

[13]  W. A. Timmer,et al.  Summary of the Delft University Wind Turbine Dedicated Airfoils , 2003 .

[14]  Christian Bak,et al.  Wind tunnel test on airfoil Riso-B1-18 with an Active Trailing Edge Flap , 2010 .

[15]  R. De Breuker,et al.  Assessment of Fatigue Load Reduction of HAWT using Smart Rotors , 2015 .

[16]  H. Bijl,et al.  Mesh deformation based on radial basis function interpolation , 2007 .