Toolkit Produced for Optimizing Floating Renewables Devices

Researchers at HR Wallingford in collaboration with the Coastal and Hydraulics Laboratory (CHL) in the U.S. have developed a toolkit for optimizing the design of floating offshore renewable energy devices by accurately simulating the response of these floating structures under realistic sea states.

A variety of concepts for floating offshore renewable energy devices are under development around the world, and each one presents its own challenges. The devices are frequently be exposed to significant wave forces and other hydrodynamic loads. While floating wind turbines aim to limit the response to wave loads, wave energy converters, for example, are tuned to have a high response to the most energetic waves.

Dr. Aggelos Dimakopoulos, Senior Engineer at HR Wallingford, said the company has focused on the fully dynamic simulation of mooring cables as they can significantly affect station-keeping and the overall response of the device, which in turn affects its energy extraction efficiency.

The toolkit consists of two main components: Computational Fluid Dynamics (CFD) using Proteus open-source software and Multi-Body Dynamics (MBD) using the Chrono open-source solver. Both models have been validated separately and together. Using a CFD model early in development can reduce costs in design optimization by performing full-scale simulations under realistic sea states, before performing laboratory tests which may be subject to practical limitations. 

The research project has been sponsored by CHL and the Engineer Research and Development Centre (ERDC) and HR Wallingford. Additional support was provided by the IDCORE doctorate program from the Energy Technologies Institute and the Research Councils Energy Programme.  

CFD can be used to provide an accurate simulation of the response of complex offshore floating structures under realistic sea states, including extreme weather conditions. Picture: HR Wallingford