Flume facility

A combined wave and tidal flume at Manchester University is available to engineering companies and consultancies looking to conduct physical tests of nearshore structures or renewable-energy devices.

Designed specifically for shallow hydraulic flows such as those found in coastal regions, the Joule Centre's Wave Flume allows simulation of realistic nearshore wave and current conditions and is particularly well suited to the evaluation of marine-energy devices and their environmental impact.

The Joule Centre, a partnership of north west universities, commercial organisations and others associated with the energy industry, was created by the Northwest Regional Development Agency. Among its many responsibilities, the centre is tasked with awarding grants to north west universities engaged in the area of energy research.

The availability of such a facility will be of interest to the growing number of companies developing technologies to harness either wave or tidal-stream energy.

Dr Tim Stallard, a lecturer at Manchester, said: 'There are very few flume facilities around the world that can simulate the effects of both current and waves, particularly directionally-spread waves. With UK wave-power levels among the world’s highest and accounting for more than half of Europe’s wave energy, the successful deployment of such technology could make a significant contribution to the UK electricity supply.'

Waves in the 20m-long facility are provided by eight of Edinburgh Designs’ piston-type wave paddles that can create regular, random, directionally-spread or grouped wave conditions. Current velocities up to 0.5m/sec at 0.45m depth are achievable and uniquely, currents can be generated simultaneously with any wave condition.

The programmable paddles and 5m width ensure that repeatable tests can be conducted without significant influence from the side walls of the flume. The flume can also be tilted by up to 10^o from the horizontal.

This feature is believed to make it the largest tilting facility of its kind anywhere in the world and will be of particular interest to companies needing to test shoreline or estuarine structures.

Key considerations for those developing marine-energy technologies are their power output, survivability and environmental impact, all of critical importance to the economic viability of this emerging industry sector. Previous experiments using the flume have helped to address such challenges.

For example, researchers developing a wave device comprising an array of vertically oscillating floats – known as the ‘Manchester Bobber’ – have used the flume facility to improve understanding of performance of an array of devices, as little is known about this for any type of wave-energy device.

The experiments enabled the team to optimise the device’s float shape as well as study arrays of tidal-stream devices to understand the effect of energy extraction on the natural flow.

While these experiments have addressed innovative renewable-energy devices, other companies might use the facility to characterise, assess and test the resilience of structures such as wind turbines, piers, jetties, coastal defences or other structures designed for deployment in nearshore waters.

Cranage is provided for test-machinery installation, along with instrumentation supported on three gantries that include capacitance wave probes and velocimeters, as well as video cameras. All instrumentation is linked to a PC interface for remote monitoring and data logging.

A Perspex basin bed ensures easy visualisation from both above and below and allows use of flow visualisation if required. Technical support is also provided at the facility, with Joule Centre representatives able to offer help in areas such as designing test programmes and advising on experimentation methods.