Non-linear aeroelasticity: An approach to compute the response of three-blade large-scale horizontal-axis wind turbines

Abstract

In this work, we present an aeroelastic model intended for three-blade large-scale horizontal-axis wind turbines. This model results from the coupling of an existing aerodynamic model and a structural model based on a segregated formulation derived in an index-based notation that enables combining very different descriptions such as rigid-body dynamics, assumed-modes techniques and finite element methods. The developed structural model comprises a supporting tower, a nacelle, which contains the electrical generator, power electronics and control systems, a hub in which the blades are connected to a rotating shaft, and three blades, which extract energy from the wind. Flexible blades are discretized into beam finite elements and the flexible tower is discretized into assumed modes. The nacelle and hub are considered rigid. To illustrate the flexibility of the structural modeling, the tower, nacelle and hub are modeled as a single kinematic chain and each blade is modeled separately. To establish the blade-hub attachments, we use constraint equations. Thus, the resulting equations are differential algebraic. We also expose a general procedure for connecting the non-matching structural and aerodynamic meshes. Finally, we present results, some of them are validations, which prove that our new approach is reliable and does have capability to capture non-linear phenomena such as centrifugal stiffening, flutter and large yaw errors, and the remaining ones correspond to the aeroelastic response of a wind turbine during a start-up maneuvering

Development of an aeroelastic code based on three‐dimensional viscous–inviscid method for wind turbine computations

“…Examples of FSI using vortex‐based methods are found in Kim et al ,. Riziotis, Manolas and Voutsinas, Gebhardt and Roccia, Branlard et al ,. Hauptmann et al .…”

“…combined a free‐wake vortex particle model called GENUVP, in which rotor blades are modeled as thin lifting surfaces, with a beam model based on Hodges as well. Gebhardt and Roccia combined an unsteady vortex lattice method with a structural model based on a segregated formulation. Branlard et al .…”

“…The coupling of MIRAS with HAWC2 is planned in the future. The aerodynamic tool, MIRAS, differs from the studies in that the blade geometry is represented in a 3D manner, and the viscous effects on the blade surface are taken into account using an integral boundary layer solver. A variety of simulation tests are provided to illustrate the versatility of MIRAS‐FLEX and how the results compare with other standardized codes.…”

Collapse analysis of wind turbine tower under the coupled effects of wind and near‐field earthquake

“…Prowell et al simulated the dynamic response of a 5‐MW wind turbine subjected to an earthquake via FAST and suggested that the bending moment at tower base in response to an earthquake in a high‐intensity region was the internal control force in wind turbine tower design. Although multisystem dynamics and modal analysis have been combined to analyze the dynamic response of wind turbines, an approach, which has developed significantly in recent years, such a method is unable to simulate the nonlinear behavior of the tower structure material and cannot precisely simulate wind turbine failure and collapse under extreme loading conditions.…”

“…Although multisystem dynamics and modal analysis have been combined to analyze the dynamic response of wind turbines, an approach, which has developed significantly in recent years, [7][8][9][10][11][12][13] such a method is unable to simulate the nonlinear behavior of the tower structure material and cannot precisely simulate wind turbine failure and collapse under extreme loading conditions.…”