Abstract
Bolund measurements were used for a blind comparison of microscale flow models. Fifty-seven models ranging from numerical to physical were used, including large-eddy simulation (LES) models, Reynolds-averaged Navier–Stokes (RANS) models, and linearized models, in addition to wind-tunnel and water-channel experiments. Many assumptions of linearized models were violated when simulating the flow around Bolund. As expected, these models showed large errors. Expectations were higher for LES models. However, of the submitted LES results, all had difficulties in applying the specified boundary conditions and all had large speed-up errors. In contrast, the physical models both managed to apply undisturbed ‘free wind’ boundary conditions and achieve good speed-up results. The most successful models were RANS with two-equation closures. These models gave the lowest errors with respect to speed-up and turbulent kinetic energy (TKE) prediction.
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Acknowledgments
We would like to thank the Danish Energy Agency (EFP07—Metoder til kortlægning af vindforhold i komplekst terræn (ENS-33033-0062), the Center for Computational Wind Turbine Aerodynamics and Atmospheric Turbulence (under the Danish Council for Strategic Research, Grant No. 09-067216) and Vestas Technology R&D for financial support. We would also like to thank former Risø DTU employee Jeppe Johansen, who envisioned the concept of a field campaign at Bolund and initiated the project together with Hans E. Jørgensen. Without the aid of the technicians in the Test and Measurement section in the wind energy division at Risø DTU, as well as all those Risø DTU employees who helped carrying masts and instruments, this project would not have been possible. Computations were made possible by the use of the Thyra PC-cluster at Risø DTU and DCSC, PC-cluster Yggdrasil. Finally, a special thanks goes to all anonymous contributors who made the blind comparison possible.
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Open Access This is an open access article distributed under the terms of the Creative Commons Attribution Noncommercial License (https://creativecommons.org/licenses/by-nc/2.0), which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
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Bechmann, A., Sørensen, N.N., Berg, J. et al. The Bolund Experiment, Part II: Blind Comparison of Microscale Flow Models. Boundary-Layer Meteorol 141, 245–271 (2011). https://doi.org/10.1007/s10546-011-9637-x
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DOI: https://doi.org/10.1007/s10546-011-9637-x
Keywords
- Bolund
- Blind comparison
- Complex terrain
- Computational fluid dynamics
- Microscale
- Validation