Comparison of loads from HAWC2 and OpenFAST for the IEA Wind 15 MW Reference Wind Turbine

Abstract

Reference wind turbines (RWTs) that reflect the state-of-the-art of current wind energy technology are necessary in order to properly evaluate innovative methods in wind turbine design and evaluation. The International Energy Agency (IEA) Wind Technology Collaboration Platform (TCP) Task 37 has recently developed a new RWT geared towards offshore floating-foundation applications: the IEA Wind 15 MW. The model has been implemented in two aeroelastic codes, OpenFAST and HAWC2, based on an underlying common ontology. However, these toolchains result in slightly different structural parameters, and the two codes utilise different structural models. Thus, to increase the utility of the model, it is necessary to compare the aeroelastic responses. This paper compares aeroelastic loads calculated using different fidelities of the blade model in OpenFAST (ElastoDyn and BeamDyn) and HAWC2 (prismatic Timoshenko without torsion and Timoshenko with fully populated stiffness matrix), where both codes use the DTU Basic controller and the same turbulence boxes to reduce discrepancies. The aeroelastic responses to steady wind, step wind and turbulent wind (per IEC 61400-1 wind class IB) are considered. The results indicate a generally good agreement between the loads dominated by aerodynamic thrust and force, especially for the no-torsion blade models. Discrepancies were observed in other load channels, partially due to differences in the asymmetric loading of the rotor and partially due to differing closed-loop dynamics, and they will be the subject of future investigations.

IEA Wind TCP Task 37: Definition of the IEA 15-Megawatt Offshore Reference Wind Turbine

“…Specifically, these tools calculated the stiffness matrices for each cross section along the blade, which were then used in OpenFAST or HAWC2. A comparison of the turbine performance between the NREL and DTU modeling tools is discussed in Rinker et al [36] Rotor performance is tightly coupled with the controller behavior and pitch schedule to reach the desired shaft revolutions per minute (rpm), torque, and thrust. The controller is described before presenting rotor performance data.…”

Precision blade deflection measurement system using wireless inertial sensor nodes

“…Since a dynamic simulation of a rotating blade is computationally demanding, a lot of effort has been put into the development of simplified but accurate structural modeling methods. The most commonly used methods are based on the blade element momentum theory (BEM), for exampe, all solvers implemented in the simulation software HAWC2 and OpenFAST 26 . Wind turbine simulation tools are nowadays extreme versatile and powerful and have become indispensable for research and development.…”

“…The most commonly used methods are based on the blade element momentum theory (BEM), for exampe, all solvers implemented in the simulation software HAWC2 and OpenFAST. 26 Wind turbine simulation tools are nowadays extreme versatile and powerful and have become indispensable for research and development.…”

Comparison of blade optimisation strategies for the IEA 15MW reference turbine

“…Furthermore, the ultimate load envelopes-when applied to a finite element (FE) model of the blade-result in significant strength and buckling failures. Whilst small discrepancies between models and aeroelastic codes are common [6], using a baseline blade with significant failures has been deemed unsuitable for the intended projects.…”