13 - Advanced Wavemaker Designs
Submitting InstitutionsHeriot-Watt University,
University of Edinburgh
Unit of AssessmentGeneral Engineering
Summary Impact TypeTechnological
Research Subject Area(s)
Engineering: Maritime Engineering, Interdisciplinary Engineering
Medical and Health Sciences: Neurosciences
Summary of the impact
Edinburgh Designs Ltd., (EDL) was spun-out to exploit ERPE research from
the original Wave Power Group. With six staff and an annual turnover
approaching £2M EDL has supplied the equipment and control systems for
wave tanks in 19 countries including the world's largest
computer-controlled wave test facility, the US Navy Manoeuvring and
Station Keeping Tank. They are currently completing the world's first
circular tank, combining waves with currents in any relative direction,
which is operated by the 6 person company, "FloWave" EDL, still run by the
founding staff, it is the world-leading supplier of wave-making technology
for scientific and recreational facilities.
The ERPE research team comprises Salter (Emeritus Professor), Professors:
Bryden; Ingram; and Wallace, Senior Lecturer Bruce, PDRAs: Davey; and
Richon, and PhD Robinson (all here throughout the period). PhD Maguire (to
2011) and former RA Taylor were previous team members.
The important research contribution underpinning this case are:
- Design of absorbing wavemaker paddles  for the accurate, controlled
generation of waves in test tanks.
- Implementation of a curved tank, with associated computer drive, to
make more effective use of small facilities .
- Design (and construction) with EDL of the worlds first wave and
current test tank facility  with ducted impeller designs [4, 5].
Waves are reflected off the surfaces of device models on test and from
the sides of tanks in which they are being tested to degrade the
predictability and repeatability of the waves in the test area. To
maximise the useful test area, the original Wave Energy Group in ERPE
built the wide tank with wave-makers along the long side, phase controlled
to propagate at up to ±20° to its perpendicular centre line. Paddles were
driven individually with signals embodying differing frequencies,
amplitudes, angles and phases to define individual wave fronts, which
summed to generate long- crested multi-spectral or mixed seas. They
developed in 2000 impedance-matched beaches at the down-wave end to
dissipate residual waves together with absorbing wave-makers that measured
the forces on the paddles and fed them back to the control systems to
modulate velocity to absorb reflected waves. However, the short sides
continued to reflect cross-waves into the test area.
This led to the construction of the Edinburgh Curved Tank in 2002 with
EPSRC support (GR/R64438/01 £143k) with 48 absorbing wave-makers in a 90°
arc, one side of matched beaches and a single glass wall. It propagates
the full palate of 1/100th scale seas, steerable through ±45°
about a radial centre line .
Edinburgh Designs Ltd (EDL) staff, all originally members of the ERPE
Wave Power Group, continue to test developments in their control software
in this tank in collaboration with ERPE staff and researchers. ERPE
researchers have continued to underpin developments in absorbing
wavemakers through numerical and physical modelling to quantify the
dependence of absorption characteristics on geometry and control
coefficients. They also established and validated in 2011 computational
fluid dynamic (CFD) techniques to numerically model wave tanks, in the
absence of flow .
Experience in the early deployment of another wave energy power
extraction technology, Pelamis — also developed within ERPE, identified
the need to be able to conduct scale-test models of wave devices under the
influence of tidal currents. This stimulated interest in tidal test
machines, not only for flowing water with controllable levels of
turbulence, but in generating flow patterns which more closely resemble
the tidal ellipses which are encountered  in practical seas.
The underpinning research has extended, beyond earlier ERPE research on
tidal current energy extraction techniques , and evolved into the
EPSRC-funded project (EP/H012745/1 £990k 2010- 14) to prove numerically
and physically the omni-directional combination of waves and currents in a
predictable and stable manner, with prescribed levels of turbulence. The
final wave plus current tank design adopted phased absorbing wavemakers
with force feedback control to enable, for the first time, the practical
combination of waves and currents in a stable manner.
This led to the awards of support from EPSRC (EP/102932C/1, £6M) to
construct the fully circular FloWave tank, 30m in diameter and 5m deep, in
ERPE at Edinburgh. With 168 force-feedback absorbing wave-makers in a 25m
circle it can propagate and absorb 1m waves in any direction relative to
an array of devices mounted on an elevating floor. Simultaneously 28 1.7m
diameter ducted flow drives will circulate water in any relative direction
at up to 1 m/s through a test area 18m wide and 2m deep. It will be used
to emulate sea conditions at the European Marine Energy Centre (EMEC) and
at other coastal sites in European waters at up to 1/20th
scale. Stable combination of flow patterns with the wave field, at
programmable levels of turbulence, is a highly demanding challenge that
has been addressed in the flow conditioning and wave-maker control.
Current is generated across the tank by using groups of impellers arranged
around its perimeter.
EPRE staff performed both computer simulations and experiments  to
provide a new method for conditioning flow from ducted impellers to remove
swirl and reduce large-scale turbulence with minimum energy loss. Each
impeller produces a single flow velocity, which may be different to its
neighbours. These differences can lead to a stepped or curved plan view
velocity profile in the test section of the tank where a plug profile is
required. EPRE staff have recently characterised the maximum allowable
velocity difference for a stable plug profile to be generated . The
same work allows a shear layer to be used to control force feedback wave
makers in the presence of current.
References to the research
References identified with * are those which best indicate the quality of
the underpinning research.
* Maguire, A.E. and Ingram, D.M.,"On Geometric Design
Considerations and Control Methodologies for Absorbing Wavemakers",
Coastal Engineering, Vol. 58, no. 2, 135-142, 2011. DOI:10.1016/j.coastaleng.2010.09.002.
This investigated the effects that geometry and control have on the
absorption characteristics of wavemakers and presented the hydrodynamic
coefficients bottom hinged flap wavemakers, as applied in reactive and
complex conjugate control to achieve increased absorption over a broader
band of frequencies.
 Davey, T., Bryden, I., Ingram, D.M., Robinson, A., Sinfield, J.L. and
Wallace, A.R., "The All- Waters Test Facility — a new resource for the
marine energy sector", Proc 4th International Conference on Ocean
Energy 2012. Available on request.
This paper described the design and construction of the fully round
FloWave, combining waves and currents in any relative direction.
 Robinson, A., Bryden, I., Ingram, D.M. and Bruce, T., "The Use of
Conditioned Axial flow Impellers to Generate a Current in a Test Tank",
Working paper accepted for publication in the Journal of Ocean Engineering
2013. Available on request.
This paper describes the initial and intermediate propulsion and flow
conditioning of currents in the round tank to achieve the required bulk
flow-speeds with acceptably low levels of turbulence above the test area
for tidal currents.
* Robinson, A., Richon, J-B., Bryden, I., Bruce, T. and Ingram, D.M.,
"Vertical mixing layer development", European Journal of Mechanics
— B Fluids, 2013. DOI:10.1016/j.euromechflu.2013.07.001.
This developed and described the final flow conditioning that creates a
shear layer between the plug of flowing water directed ahead of the
wave-makers in the round tank, to avoid interference with the
force-feedback of the absorbing wave-makers and improve stability of
* Salter, S.H. and Taylor, J.R.M., "Vertical-axis tidal-current
generators and the Pentland Firth", Proceedings Institution of Mechanical
Engineers, Part A: Journal of Power and Energy, Vol. 221, No. 2, pp.
181-199, 2007. DOI:10.1243/09576509JPE295.
18 GS citations.
This describes an early design of tidal current energy extraction
technique based on a vertical- axis approach. It extends 2 ideas
introduced in papers from the 2005 World Renewable Energy Conference.
Details of the impact
Edinburgh Designs Ltd., the staff spin-out from the ERPE wave energy
specialises in the design, manufacture and installation of a wide range of
wave and tidal generators. Since 1987 EDL has established itself as a
world leader in the provision of hydrodynamic test equipment, including:
- flap-type ocean wave generators;
- piston-type coastal wave generators;
- wave generating software and measuring equipment;
- beaches and movable floors;
- scientific tidal, wind and flow tanks and recreational tank equipment.
EDL directly employs 6 full-time staff with a turnover exceeding £2M per
annum [S1]. They sub- contract manufacture and installation to local and
UK companies, depending on the location of each installation, creating
significant indirect employment and onward turnover.
They have supplied over 1000 wave-makers to 50 installations in 19
countries into academic, governmental, defence and recreational facilities
) including every academic installation in the UK. Examples of
recreational wave makers are surf wave pools, rapid river rides, theme
park waves and flow rides. www.edesign.co.uk/product/leisure/
shows the current range of leisure designs.
Since 2008 EDL has:
- supplied the CoAST laboratory at Plymouth University with a coastal
basin, ocean tank, sediment flume and tilting tank. All four rectangular
tanks are equipped with wave-makers and straight-flow current generators
and the ocean tank has a hydraulic moving floor [S3].
- Installed in 2011 wave-making equipment in the 260 m Marin
Depressurised Wave Basin at Waginengen in the Netherlands to generate
bow-on and beam waves during ship-towing tests. For the first time this
enabled the investigation into cavitation in a wave environment and the
study of air entrapment under reduced ambient air pressure.
- Created the giant wave and flood scenes for 2012 film The
Impossible on the 2004 Indian Ocean tsunami, www.edesign.co.uk/2012/12/edinburgh-designs-creates-the-impossible-wave/
- Commissioned on completion, in 2013, the Manoeuvring and Sea Keeping
Basin for the US Navy David Taylor Facility in Maryland [S4], with 216
flap generators producing over 1 MW of wave energy, to become the
largest computer-controlled wave tanks in the world for testing ship
The detailed technical collaboration between ERPE and EDL in wave-maker
design and testing was recognised by the 2011 joint award of
(EP/H012745/1, £2.1 Million with EDL) to further explore the design of
several new wave and current generators for stable wave generation in
multi- directional combined tanks and prove that this concept could be
applied to a round tank. This led to the subsequent award of EP/102932C/1,
£6 Million, to construct the All-UK Waters Combined Wave and Current Test
Facility  and subsequent formation of the subsidiary company FloWave TT
with 6 full-time staff. Complementing these investments and subscription
by the University of Edinburgh, Scottish Enterprise awarded a further £1
Million to enhance the scientific and staff provision increasing the total
investment to £11.2 Million.
"As Managing Director I can verify that Edinburgh Designs continues to
have strong technical collaborations with the Wave Power Group at ERPE.
In particular we have adopted, into our design portfolio, ERPE research
on new methods for integrating waves with current flow generated by an
array of impellers. The new Flowave tank has 28 computer controlled
impellers arranged in a circle. Each can be programmed so that the
direction and velocity of the combined flow within the basin can be
controlled in real time. This was a unique opportunity to combine our
experience of constructing previous project with new research work
conducted within the University. We are very pleased to have been
selected to design the new Flowave facility as it further extends our
capability from wave makers into full 3D marine current test tank
design", Managing Director, Edinburgh Designs [S1].
"Stephen Salter and his colleagues have provided many technical
advances in the design of wavemakers and their associated drivers for
wave tanks, which have been installed worldwide through the spin-out
company Edinburgh Designs. This world-leading technical capability has
enabled recent funding for the construction of the new FloWave facility,
which gives the UK a world-wide lead in simulating ocean conditions for
testing tidal and wave energy devices." Chief Scientific Advisor,
Department for Energy and Climate Change [S2].
This world-unique facility, which combines recent ERPE research [4, 5]
with EDL's commercial expertise, http://www.edesign.co.uk/portfolio/edinburgh-university/,
has had already significant impact on the marine energy and other sectors,
with a pipeline of device developers and academic researchers already
established. It emulates at up to 1/20th scale the combination
of wave and tidal conditions anywhere around European coastlines. The
facility simulates conditions at EMEC as a pre-proving ground for
technology developers and investors as part of the UK commercial test
capability, which ranges from 1:100 scale testing in laboratories to full
scale at EMEC and at WaveHub in Cornwall.
Sources to corroborate the impact
[S1] Managing Director, Edinburgh Designs Ltd., see comments included in
[S2] Chief Scientific Advisor, Department of Energy and Climate Change,
see comments included in Section 4.
the Plymouth Marine facility.
shows, the US Navy, Maryland facility.