The Development and Validation of Aero-Elastic Codes - Simulation of Wind Energy Converters (SiWEC) / Offshore Code Comparison Collaboration Continuation, with Correlation (OC5)
The calculation of load assumptions is crucial for the development and optimisation of wind energy plant. Today these loads are determined through the use of so-called aero-elastic codes as highly-specialised simulation tools. The objective of these simulations is to produce results that are as precise and realistic as possible, which is the only way to ensure the proper design of modern wind energy systems. Achieving this goal requires the continuous development of the relevant programmes based on the latest empirical data. For this reason, the simulation of wind turbines is one of the main research areas at the Department of Wind Energy Technology.
Simulation of Wind Energy Converters (SiWEC)
In collaboration with Windrad Engineering GmbH, the Department of Wind Energy Technology is developing the in-house Simulation of Wind Energy Converters (SiWEC) simulation programme, in which the wind turbine is modelled as a multibody mechanical system. This relies upon the strict configuration of the model as a series of mechanically coupled sub-models (generator, tower, rotor etc.). The simulation programme utilises state-of-the-art rotor element theory and a detailed model of the foundation-subsoil interactions for all on and offshore foundations. By using efficient mathematical solution methods, the SiWEC enables the precise and rapid computation of the design-relevant wind turbine loads. A graphic output (see graphic) also enables the visualisation of the modelled wind turbine, which in turn provides an additional layer of quality control, for example during the computation of special load cases.
Offshore Code Comparison Collaboration Continuation, with Correlation (OC5)
A crucial element in the developmental and improvement of simulation programmes is the validation of the simulation results against empirical data. For this reason, the Department of Wind Energy Technology is participating in the Offshore Code Comparison Collaboration Continuation, with Correlation (OC5) project with its SiWEC programme. In addition to the University of Rostock, a further 28 partner organisations from 12 different countries are collaborating in the (OC5) project. The main objectives of OC5 are:
- To assess the precision and reliability of simulation results
- The identification and validation of the potential and limitations of the simulation programmes
- Conducting further research into and refining analytical approaches
- The identification of future research and development problems in the field of aero-elastic codes
OC5 comprises three phases, whereby the empirical data from a wind turbine installed in the North Sea are being used for validation purposes in the current phase, which is Phase III. The wind turbine in questions is a 5MW system of the REpower 5M type, which is installed in Germany’s first offshore wind farm - Alpha Ventus - on a jacket-type tower manufactured by OWEC Tower. As part of the RAVE-Initiative (Research at Alpha Ventus), this wind turbine was fitted with a plethora of sensors prior to installation, which supply the OC5 project with a wealth of empirical data relating loads, deformations and acceleration forces at various points throughout the structure. Phase III of the project is scheduled to run for 16 months from January 2017 to April 2018.
We would like to offer our heartfelt thanks to Senvion S.A. and OWEC Towers AS for providing the data needed to model the system under study in the simulation tools, as well as to NREL and IWES for organising and coordinating the OC5 project.