Context

A key phase in the development of a wind energy project is a comprehensive assessment of the inflow wind conditions. This is essential to determine the financial feasibility of a project. Whilst the characteristics of the mean flow (like speed, direction) are relatively simple to assess by modelling or measurement tools, a lack of confidence in the characterization of wind fluctuations, i.e., turbulence, over a range of scales, has subsequently resulted in high levels of conservativeness being employed by wind turbine designers.

Objective

To provide methodologies and tools for a comprehensive assessment of turbulence at prospective offshore wind sites

Scientific content

Review and redefinition of turbulence metrics for the offshore wind applications

Measurements of atmospheric turbulence

• Improvement of reconstruction procedures of turbulence metrics derived from lidar profiler
• Derivation of turbulence from scanning lidars in dual-Doppler configuration
• Investigation and implementation of universal multifractals for higher-order turbulence statistics
• Joint measurement campaign at Normandy test site to support method development

Modeling of turbulent flows

• Calibration of turbulence length-scales (100m – 1,000 m) using large eddy simulations and incorporate them into mesoscale model
• Adaptation of numerical model settings to derive recommendations for turbulence data simulation
• Assessment of different lidar configurations’ ability to reconstruct turbulence information through virtual lidars in large eddy simulationwind fields

Reconstruction of offshore wind metrics using data-driven methods

• Use of statistical and machine learning models to estimate offshore wind metrics from onshore measurements and numerical models outputs
• Comparison of data-driven models and large eddy simulations for offshore turbulence forecasting

Expected results

• Collection of a new turbulence dataset
• Methodology for the reconstruction of turbulence from wind lidars (ground-based, floating and scanning)
• Industry applicable turbulence from meso-scale modelling
• Site-specific transfer functions, combining observations and model output, to derive offshore information from onshore information

RESSOURCES

DRACCAR-NEMO project sheet (PDF)

Partners and funding

This project is led by France Energies Marines and Fraunhofer IWES.

The total budget project is €2,032K.

This project receives funding from France Energies Marines and its members and partners, as well as French State funding managed by the National Research Agency under the France 2030 investment plan. It also benefits from the financial support of Ifremer, Pôle Mer Méditerranée, Occitanie and SUD Provence-Alpes-Côte d’Azur regions. 

Photo credit: ELG21/Pixabay