Evaluating the fidelity and robustness of calibrated numerical model predictions: An application on a wind turbine blade
Abstract
Purpose
Numerical models are being increasingly relied upon to evaluate wind turbine performance by simulating phenomena that are infeasible to measure experimentally. These numerical models, however, require a large number of input parameters that often need to be calibrated against available experiments. Owing to the unavoidable scarcity of experiments and inherent uncertainties in measurements, this calibration process may yield non-unique solutions, i.e. multiple sets of parameters may reproduce the available experiments with similar fidelity. The purpose of this paper is to study the trade-off between fidelity to measurements and the robustness of this fidelity to uncertainty in calibrated input parameters.
Design/methodology/approach
Here, fidelity is defined as the ability of the model to reproduce measurements and robustness is defined as the allowable variation in the input parameters with which the model maintains a predefined level of threshold fidelity. These two vital attributes of model predictiveness are evaluated in the development of a simplified finite element beam model of the CX-100 wind turbine blade.
Findings
Findings of this study show that calibrating the input parameters of a numerical model with the sole objective of improving fidelity to available measurements degrades the robustness of model predictions at both tested and untested settings. A more optimal model may be obtained by calibration methods considering both fidelity and robustness. Multi-criteria Decision Making further confirms the conclusion that the optimal model performance is achieved by maintaining a balance between fidelity and robustness during calibration.
Originality/value
Current methods for model calibration focus solely on fidelity while the authors focus on the trade-off between fidelity and robustness.
Keywords
Acknowledgements
The authors thank Francois Hemez of Los Alamos National Laboratory and Yakov Ben-Haim of Technion Israel Institute of Technology for the assistance with info-gap decision theory. The authors also wish to express the gratitude to Stuart Taylor of Los Alamos National Laboratory for supplying the experimental configuration and modal analysis measurements of the CX-100 wind turbine blade, and to D.J. Luscher for supplying the scripts for the NLBeam geometrically exact beam model.
Citation
Stevens, G., Van Buren, K., Wheeler, E. and Atamturktur, S. (2015), "Evaluating the fidelity and robustness of calibrated numerical model predictions: An application on a wind turbine blade", Engineering Computations, Vol. 32 No. 3, pp. 621-642. https://doi.org/10.1108/EC-09-2013-0217
Publisher
:Emerald Group Publishing Limited
Copyright © 2015, Emerald Group Publishing Limited