Dynamics of floating water-wave energy extraction devices

cab5b85e-b688-4970-8030-b4dfb4e869e7

Closed

EPSRC
EPSRC
EPSRC
EPSRC
EPSRC

£1,458,985

May 31, 2013

May 31, 2016

The ocean is, essentially, a perpetual motion machine with vast reservoirs of energy, some of which is delivered to the shoreline in the form of waves. The extraction of this energy is one of the great under-utilized branches of renewable energy, and the UK is well placed to exploit this energy: the UK shoreline attracts about 35% of the total wave energy available to ALL of Europe.

Although various wave energy converters (WECs) for the extraction of energy from ocean waves have been around
for a long time, it is only recently that both government and industry have developed a strong and ambitious interest,
and the number of potential WECs for extraction of energy from the ocean wave environment is growing. The interest in this proposal is the OWEL WEC. It is a floating rectangular device open at one end to allow waves in. It is a moored deep-water offshore structure interacting with ocean waves. The wave energy is extracted via a power take-off system. It is one of the most difficult WECs to model.

The interest in this proposal is to tackle three main mathematical modelling issues: (1) the dynamics of the waves once they are trapped inside the vessel, (2) the effect of resonance between components, and (3) the dynamic feedback due to multi-fold coupling between interior waves, the ambient ocean wave field, vessel dynamics and mooring dynamics. The ultimate goal is to build up a model which, starting with an ambient ocean wave field, describes the detailed process whereby this energy is extracted and delivered to the power take off system.

Potential Impact:
The mathematical modelling of the OWEL configuration is one of the most difficult of the WECs to model. It requires a novel combination of fluid mechanics, geometric mechanics, numerical analysis, modelling and applied mathematics. The principal impact will be on the design and implementation of the current succession of WECs by OWEL. This proposed project
will be getting in on the ground floor since the first prototype is scheduled for deployment in 2013 and long term plans include a succession of improved models over the next 20 years. This impact will be facilitated by regular communication, punctuated by quarterly meetings at the Bristol office or at Surrey.

The principal features of the OWEL model are generic: interior fluid motion in a floating body, dynamics of floating bodies in waves, and resonances due to multi-fold coupling are all features of a range of marine systems. Hence the mathematical models, analytical tools, and numerical methods will have independent interest.

The practical aspects of impact through dissemination will involve a website, publications, attendance at conferences, and the Surrey Themed Semesters in Spring 2013 and Spring 2015.

There will be a range of impact on the postdoctoral researcher as well. The project offers the opportunity to dig deeply into both fundamental topics, as well as applied and application-oriented topics. The development of expertise in modelling and analysis of the OWEL configuration would position the PDRA to develop into a leading contributor to the mathematical modelling of wave energy extractors, and a person trained in this direction will be extremely important in the long term national strategy for wave energy
extraction in the UK.