Aerodynamic modeling of wind turbine loads exposed to turbulent inflow and validation with experimental data

Bangga, Galih; Lutz, Thorsten

doi:10.1016/j.energy.2021.120076

Cited by 32 publications

(31 citation statements)

References 29 publications

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“…For this work the polars used are based on extraction from blade resolved CFD simulations assuming a fully turbulent boundary layer (Hansen et al, 1997;Schepers et al, 2021). In the last 10% of the blade the 3D CFD polar is replaced with 2D CFD data (Bangga, 2018;Bangga and Lutz, 2021) to prevent tip loss effects being double-counted. In the IEA Wind Task 29 this CFD-extracted polar was shown to significantly outperform previous versions found from wind tunnel testing (Schepers et al, 2021) when comparing blade loading predictions with DanAero measurements.…”

Section: Actuator Line Methods Coupled To Aeroelastic Solver Flex5mentioning

confidence: 99%

Validation of Aeroelastic Actuator Line for Wind Turbine Modelling in Complex Flows

et al. 2022

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The actuator line method is a widely used technique to model wind turbines in computational fluid dynamics, as it significantly reduces the required computational expense in comparison to simulations using geometrically resolved blades. Actuator line coupled to an aeroelastic solver enables not only the study of detailed wake dynamics but also aeroelastic loads, flexible blade deformation and how this interacts with the flow. Validating aeroelastic actuator line predictions of blade loading, deflection and turbine wakes in complex inflow scenarios is particularly relevant for modern turbine designs and wind farm studies involving realistic inflows, wind shear or yaw misalignment. This work first implements a vortex-based smearing correction in an aeroelastic coupled actuator line, and performs a grid resolution and smearing parameter study which demonstrates significant improvement in the blade loading and in the numerical dependencies of predicted thrust and power output. A validation is then performed using a 2.3 MW turbine with R = 40 m radius, comparing against blade resolved fluid-structure interaction simulations and full-scale measurement data, in both laminar and turbulent inflows including both high shear and high yaw misalignment. For an axisymmetric laminar inflow case, the agreement between blade resolved and actuator line simulations is excellent, with prediction of integrated quantities within 0.2%. In more complex flow cases, good agreement is seen in overall trends but the actuator line predicts lower blade loading and flapwise deflection, leading to underpredictions of thrust by between 5.3% and 8.4%. The discrepancies seen can be attributed to differences in wake flow, induction, the reliance of the actuator line on the provided airfoil data and the force application into the computational domain. Comparing the wake between coupled actuator line and blade resolved simulations for turbulent flow cases also shows good agreement in wake deficit and redirection, even under high yaw conditions. Overall, this work validates the implementation of the vortex-based smearing correction and demonstrates the ability of the actuator line to closely match blade loading and deflection predictions of blade resolved simulations in complex flows, at a significantly lower computational cost.

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Section: Actuator Line Methods Coupled To Aeroelastic Solver Flex5mentioning

confidence: 99%

Validation of Aeroelastic Actuator Line for Wind Turbine Modelling in Complex Flows

et al. 2022

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“…In contrast, all turbine models rely on tabulated lift and drag values that do include them. Bangga and Lutz [32] therefore argue that a closer agreement in F t not necessarily implies a better model prediction. On the other hand, the differences in F t are qualitatively consistent with the differences in the power, indicating that the neglected component cannot have a major contribution.…”

Section: Power and Loads Of The Downstream Turbinementioning

confidence: 98%

“…For the majority of the models this error is found in the range of 15e20%. Bangga and Lutz [32] compared BEM and fully resolved rotor simulations of DanAero cases in unwaked inflow conditions. The average relative errors of F 4 n reported for the four blade sections lie in the range of 3e9%.…”

Section: Model Evaluationmentioning

confidence: 99%

Wind Turbine Response in Waked Inflow: A Modelling Benchmark Against Full-Scale Measurements

et al. 2021

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“…The computational settings in the present studies were prepared according to the previous works for airfoil, helicopter wind turbine cases, e.g., ref. [29][30][31][39][40][41]. In these studies, the employed WENO scheme was able to model the turbulent kinetic energy of the flow and the decay of atmospheric turbulence fairly well compared to reference data, as illustrated for the NACA 0021 airfoil simulation results at 60 • incidence in Figure 3.…”

Section: Computational Fluid Dynamicsmentioning

confidence: 91%

“…[28] The FLOWer code was continuously extended by the Institute of Aerodynamics and Gas Dynamics (IAG) at the University of Stuttgart for the simulations of wind turbine components, including the usages of high fidelity eddy resolving computations and high order flux discretizations. [29][30][31] The code made use of a central space discretization with artificial dissipation being calculated in relation to the grid cell aspect ratio. [32] This approach was robust and well suited for parallel application.…”

Section: Computational Fluid Dynamicsmentioning

confidence: 99%

Aerodynamic and Acoustic Simulations of Thick Flatback Airfoils Employing High Order DES Methods

Bangga

Seel

Lutz

et al. 2022

Advcd Theory and Sims

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The results of high fidelity aerodynamic and acoustic computations of thick flatback airfoils are reported in the present paper. The studies are conducted on a flatback airfoil having a relative thickness of 30% with the blunt trailing edge thickness of 10% relative to chord. Delayed Detached‐Eddy Simulation (DDES) approaches in combination with high order (5th) flux discretization WENO (Weighted Essentially Non‐Oscillatory) and l2Roe$l^{2}Roe$ Riemann solver are employed. Two variants of the DES length scale calculation methods are compared. The results are validated against experimental data with good accuracy. The studies provide guideline on the mesh and turbulence modeling selection for flatback airfoil simulations. The results indicate that the wake breakdown is strongly influenced by the spanwise resolution of the mesh, which directly contributes to the prediction accuracy especially for drag force and noise emission. The Reynolds normal stress u′u′¯$\overline{u^{\prime }u^{\prime }}$ and the u′v′¯$\overline{u^{\prime }v^{\prime }}$ Reynolds stress component have the largest contributions on the mixing process, while the contribution of the u′w′¯$\overline{u^{\prime }w^{\prime }}$ component is minimal. Proper orthogonal decomposition is further performed to gain deeper insights into the wake characteristics.

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Aerodynamic modeling of wind turbine loads exposed to turbulent inflow and validation with experimental data

Cited by 32 publications

References 29 publications

Validation of Aeroelastic Actuator Line for Wind Turbine Modelling in Complex Flows

Validation of Aeroelastic Actuator Line for Wind Turbine Modelling in Complex Flows

Wind Turbine Response in Waked Inflow: A Modelling Benchmark Against Full-Scale Measurements

Aerodynamic and Acoustic Simulations of Thick Flatback Airfoils Employing High Order DES Methods

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