Title: Evaluation of different wind fields for the investigation of the dynamic response of offshore wind turbines

Abstract

As the size of offshore wind turbines increases, a realistic representation of the spatiotemporal distribution of the incident wind field becomes crucial for modeling the dynamic response of the turbine. The International Electrotechnical Commission (IEC) standard for wind turbine design recommends two turbulence models for simulations of the incident wind field, the Mann spectral tensor model, and the Kaimal spectral and exponential coherence model. In particular, for floating wind turbines, these standard models are challenged by more sophisticated ones. The characteristics of the wind field depend on the stability conditions of the atmosphere, which neither of the standard turbulence models account for. The spatial and temporal distribution of the turbulence, represented by coherence, is not modeled consistently by the two standard models. In this study, the Mann spectral tensor model and the Kaimal spectral and exponential coherence model are compared with wind fields constructed from offshore measurements and obtained from large-eddy simulations. Cross sections and durations relevant for offshore wind turbine design are considered. Coherent structures from the different simulators are studied across various stability conditions and wind speeds through coherence and proper orthogonal decomposition mode plots. As expected, the standard models represent neutral stratification better than they do stablemore » and unstable. Depending upon the method used for generating the wind field, significant differences in the spatial and temporal distribution of coherence are found. Consequently, the computed structural design loads on a wind turbine are expected to vary significantly depending upon the employed turbulence model. The knowledge gained in this study will be used in future studies to quantify the effect of various turbulence models on the dynamic response of large offshore wind turbines.« less

Authors:

Nybø, Astrid  ^[1];

• Search DOE PAGES for author "Nybø, Astrid"
• Search DOE PAGES for ORCID "0000-0002-7438-7936"

Nielsen, Finn Gunnar  ^[1];

• Search DOE PAGES for author "Nielsen, Finn Gunnar"
• Search DOE PAGES for ORCID "0000-0002-1576-2409"

Reuder, Joachim  ^[1];

• Search DOE PAGES for author "Reuder, Joachim"
• Search DOE PAGES for ORCID "0000-0002-0802-4838"

Churchfield, Matthew J.  ^[2];

• Search DOE PAGES for author "Churchfield, Matthew J."
• Search DOE PAGES for ORCID "0000-0001-9906-7288"

Godvik, Marte ^[3]

---

+ Show Author Affiliations

1. Univ. of Bergen (Norway)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
3. Univ. of Bergen (Norway); Equinor, Bergen (Norway)

Publication Date:

Fri May 08 00:00:00 EDT 2020

Research Org.:

National Renewable Energy Laboratory (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Wind Energy Technologies Office

OSTI Identifier:

1660020

Report Number(s):

NREL/JA-5000-76690
Journal ID: ISSN 1095-4244; MainId:9351;UUID:cc4bd23e-c90c-4650-9b0b-1e98109d21da;MainAdminID:13780

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

Wind Energy

Additional Journal Information:

Journal Volume: 23; Journal Issue: 9; Journal ID: ISSN 1095-4244

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

17 WIND ENERGY; coherence; offshore wind turbines; proper orthogonal decomposition modes; turbulence models; wind fields