A new coupled model for the equivalent roughness heights of wind farms. (June 2021)
- Record Type:
- Journal Article
- Title:
- A new coupled model for the equivalent roughness heights of wind farms. (June 2021)
- Main Title:
- A new coupled model for the equivalent roughness heights of wind farms
- Authors:
- Zhang, Huan
Ge, Mingwei
Liu, Yongqian
Yang, Xiang I.A. - Abstract:
- Abstract: Accurate parameterization of wind farms' equivalent roughness heights is critical to meso-scale climate simulations as well as power predictions of wind turbines. A notable inadequacy of the existing models is that the results sensitively depend on s x / s y, where s x and s y are the dimensionless streamwise and spanwise spacing of the turbines. To understand the issue, we conduct large-eddy simulations (LESs) for three types of quasi-infinite wind farms with moderate, large, and small s x / s y . We find that the wind speed at the rotor is different from the horizontally averaged wind speed at the hub height, and this is particularly true for wind farms with small s x / s y . This flow inhomogeneity at the hub height plays an important role in determining wind farms' equivalent roughness height but is often neglected in the existing models. Accounting for the flow inhomogeneity at the hub height, we propose a new coupled top-down/bottom-up model for the equivalent roughness heights of wind farms. Our model is compared with the existing models and our LESs. The results show that the proposed model is able to predict the equivalent roughness height of all types of wind farms irrespective of s x / s y 's value. Highlights: The mean profile of wind farm boundary layer shows a three-layer structure. Flow inhomogeneity at the hub height is important for the model of wind farm. A new model is proposed for the equivalent roughness heights of wind farms. The model isAbstract: Accurate parameterization of wind farms' equivalent roughness heights is critical to meso-scale climate simulations as well as power predictions of wind turbines. A notable inadequacy of the existing models is that the results sensitively depend on s x / s y, where s x and s y are the dimensionless streamwise and spanwise spacing of the turbines. To understand the issue, we conduct large-eddy simulations (LESs) for three types of quasi-infinite wind farms with moderate, large, and small s x / s y . We find that the wind speed at the rotor is different from the horizontally averaged wind speed at the hub height, and this is particularly true for wind farms with small s x / s y . This flow inhomogeneity at the hub height plays an important role in determining wind farms' equivalent roughness height but is often neglected in the existing models. Accounting for the flow inhomogeneity at the hub height, we propose a new coupled top-down/bottom-up model for the equivalent roughness heights of wind farms. Our model is compared with the existing models and our LESs. The results show that the proposed model is able to predict the equivalent roughness height of all types of wind farms irrespective of s x / s y 's value. Highlights: The mean profile of wind farm boundary layer shows a three-layer structure. Flow inhomogeneity at the hub height is important for the model of wind farm. A new model is proposed for the equivalent roughness heights of wind farms. The model is validated via LES and works better than the existing models. … (more)
- Is Part Of:
- Renewable energy. Volume 171(2021)
- Journal:
- Renewable energy
- Issue:
- Volume 171(2021)
- Issue Display:
- Volume 171, Issue 2021 (2021)
- Year:
- 2021
- Volume:
- 171
- Issue:
- 2021
- Issue Sort Value:
- 2021-0171-2021-0000
- Page Start:
- 34
- Page End:
- 46
- Publication Date:
- 2021-06
- Subjects:
- Quasi-infinite wind farms -- Equivalent roughness model -- Large-eddy simulation -- Wake layer
Renewable energy sources -- Periodicals
Power resources -- Periodicals
Énergies renouvelables -- Périodiques
Ressources énergétiques -- Périodiques
333.794 - Journal URLs:
- http://www.sciencedirect.com/science/journal/09601481 ↗
http://www.elsevier.com/journals ↗
http://www.journals.elsevier.com/renewable-energy/ ↗ - DOI:
- 10.1016/j.renene.2021.02.076 ↗
- Languages:
- English
- ISSNs:
- 0960-1481
- Deposit Type:
- Legaldeposit
- View Content:
- Available online (eLD content is only available in our Reading Rooms) ↗
- Physical Locations:
- British Library DSC - 7364.187000
British Library DSC - BLDSS-3PM
British Library HMNTS - ELD Digital store - Ingest File:
- 17393.xml