Our group studies wind energy using computer simulations. Using the immersed boundary method and fluid-structure interaction, we simulate the interaction of air flows with wind turbines with the structure geometry resolved. For the wind turbines, we also use actuator disk model, actuator line model, and actuator surface model for simulations at different levels of sophistication. Our simulations are performed in the real atmospheric and oceanic settings. We also connect our CFD-based study with field and laboratory measurements, reduced-order modeling, and active control.
Besides wind energy on land, our group performs extensive research on offshore wind energy and pioneers in this emerging area. Our study focuses on the investigation of the effect of ocean waves on wind energy in marine atmospheric boundary layer and the dynamics of floating wind turbines. For the study of wave effect on wind energy, we have performed coupled wave simulation and wind LES together with turbine modeling for the investigation of the flow fields in the space-time domain with the wave phases resolved. We considered wind turbulence interacting with broadband irregular waves for duration- and fetch-limited growing wind seas, fully developed seas, and wind seas in the presence of swells. To the best of our knowledge, our study was the first simulation-based study that addresses the dynamical coupling among wind, waves, and wind farm with all the essential nonlinear interaction processes directly captured in a wave-phase-resolving context. Our simulations provide a useful tool for assessing ocean wind and wave resources. The study can also assist wind and wave climate forecast, which is valuable for the optimizing of wind turbine operation and grid scheduling.
Recently, we have made substantial progresses in the simulation of the dynamics of floating wind turbines. We have developed an advanced numerical method for simulating real life complex floating structures and their interaction with realistic ocean wave and wind fields. To efficiently deal with the computational challenge of large disparity of scales associated with such type of problems, we adopted a partitioned far-field/near-field approach. Wind LES coupled with HOS simulation of waves is carried out in the far-field domain to provide realistic wind and wave inflow conditions. In the near-field domain, an advanced fluid-structure interaction method together with the level-set method is used to study the interaction of complex floating structures with wind and waves. To demonstrate and validate the capability of our numerical capability, we have simulated a 13.2 MW offshore floating wind turbine under realistic ocean wind and wave conditions in Pacific Northwest. It is found that our simulation is able to capture the turbine response in the six degrees of freedom by considering the platform-wave interaction, the effect of the turbulent wind on the turbine, and the gyroscopic effect of the rotor.
Selected publications:
- Swenson, L., Gao, L., Hong, J. & Shen, L. (2022), "An efficacious model for predicting icing-induced energy loss for wind turbines," Applied Energy, Vol. 305, 117809.
- Yang, X., Milliren, C., Kistner, M., Hogg, C., Marr, J., Shen, L. & Sotiropoulos, F. (2021), “High-fidelity simulations and field measurements for characterizing wind fields in a utility-scale wind farm,” Applied Energy, Vol. 281, 116115.
- Foti, D., Yang, X., Shen, L. & Sotiropoulos, F. (2019), “Effect of wind turbine nacelle on turbine wake dynamics in large wind farms,” Journal of Fluid Mechanics, Vol. 869, pp.1-26.
- Lyu, P., Chen W., Li, H. & Shen, L. (2019), “A numerical study on the development of self-similarity in a wind turbine wake using an improved pseudo spectral large-eddy simulation solver,” Energies, 12, 643.
- Calderer, A., Guo, X., Shen, L. & Sotiropoulos, F. (2018), “Fluid-structure interaction simulation of floating structures interacting with complex, large-scale ocean waves and atmospheric turbulence with application to floating offshore wind turbines,” Journal of Computational Physics, Vol. 355, pp.144-175.
- Lyu, P., Park, S.G., Li, H. & Shen, L. (2018), “A coupled wind-wave-turbine solver for offshore wind farm,” Proceedings of International Offshore Wind Technical Conference.
- Calderer, A., Guo, X., Shen, L. & Sotiropoulos, F. (2014), “Coupled fluid-structure interaction simulation of floating offshore wind turbines and waves: a large eddy simulation approach,” Journal of Physics, Vol. 524, Proceedings of The Science of Making Torque from Wind.
- Yang, D., Meneveau, C. & Shen, L. (2014), “Effect of downwind swells on offshore wind energy harvesting — a large-eddy simulation study,” Renewable Energy, 70, pp.11-23.
- Yang, D., Meneveau, C. & Shen, L. (2014), “Large-eddy simulation of offshore wind farm,” Physics of Fluids, 26, 025101.
- Yang, D., Meneveau, C. & Shen, L. (2013), “Large-eddy simulation based study of offshore wind turbine array boundary layers,” Proceedings of 2013 International Conference on Aerodynamics of Offshore Wind Energy Systems and Wakes.