The first ever World Tsunami Awareness Day is take place this year on 05 November.
The UN office for Disaster Risk Reduction (UNISDR) hope the day will raise tsunami awareness and share innovative approaches to risk reduction. An example of one of those innovative approaches can be found at research and development facilities in the heart of England.
Hydraulic engineering specialists, HR Wallingford, have developed the largest specialist tsunami simulator in Europe. It uses almost 70,000 litres of water in a 70m long x 4m wide channel to produce simulated tsunamis.
Hydraulic engineering specialists, HR Wallingford, unveiled their latest generation tsunami simulator, the most realistic yet, in early September 2016 at their world-leading facilities in Oxfordshire, UK.
The Tsunami Simulator, which is installed in HR Wallingford’s Fast Flow Facility, is being part-funded by a €1.9 million European Research Council Starting Grant ‘URBAN WAVES’. Professor Tiziana Rossetto‘s team from UCL EPICentre (University College London), and researchers from HR Wallingford, will use the facility to test coastal defences and urban environments for their tsunami resilience, which will ultimately lead to improved engineering guidance to aid disaster management worldwide.
HR Wallingford, an independent engineering and environmental hydraulics organisation based in Oxfordshire, built its 1st generation Tsunami Simulator in 2008. Preliminary tests proved the concept of using a pneumatic system, similar to that used for some large leisure or surfing pools, to generate realistic, stable trough-led tsunami waves.This simulator was used to successfully reproduce the 2004 Indian Ocean tsunami at a scale of 1:50. A 2nd generation Tsunami Simulator was able to generate more complicated or longer waves, thus able to simulate the 2011 Japanese tsunami with its particularly complex wave profile.
This 3rd generation Tsunami Simulator, the largest specialist tsunami device in Europe, has been installed in a 70 m long and 4 m wide channel, and uses 70,000 litres of water to simulate a tsunami. At the same scale of 1:50, it improves the generation of both crest-led and trough-led tsunamis, and will enable – for the first time – the simulation of a tsunami impact on urban areas, through modelling in detail the effects that tsunamis have on coast defences, and how water is channelled around clusters of buildings. This will provide the most accurate testing of the forces acting on buildings.
Tests with the Tsunami Simulator will also evaluate whether flood defences are effective against tsunamis, or might amplify their destructiveness by allowing flood waters to build up in front of defences and then, when they fail, suddenly inundate areas behind, causing more devastation to areas previously thought to be safe.
Prof. Tiziana Rossetto, Professor of Earthquake Engineering, and Director of UCL EPICentre, who is leading the research, said:
“Tsunamis can be exceptionally destructive when they hit buildings, yet we really don’t know a great deal about how the massive horizontal forces they generate act on buildings to cause damage.
“The challenge has been to build a testing facility where we can accurately model these forces on a variety of physical structures, as well as how the forces change or are magnified by the way buildings are clustered together in coastal towns and cities.
“Our research at this unique facility will have far-reaching implications for both building and urban design in areas at risk of tsunamis, and could help mitigate some of the most devastating risks of the phenomena to both human lives and the land they depend on.”
Prof. William Allsop, Technical Director of Maritime Structures at HR Wallingford, who is co-supervising the development of the facility and subsequent research, added:
“We are very pleased to work with the team at UCL. This new project builds on our earlier collaborative research. In our initial work, we modelled the facility using advanced Computational Fluid Dynamics tools developed at HR Wallingford, thus ensuring that this facility has the widest possible capabilities in modelling tsunamis.
“The unique feature of the new HR Wallingford Tsunami Simulator is that its tank-based generator allows us to generate a realistic tsunami wave, so simulating the full duration of a tsunami wave – a 20 minute wave duration is scaled to just over two minutes in the lab. Almost no other device can do this.”
UCL EPICentre will be at HR Wallingford undertaking the experimental phase of the ‘URBAN WAVES’ project until October 2016, after which the Tsunami Simulator might be made available for use by other external researchers and organisations. The results of the studies will appear in a series of conference and scientific journal papers over the next few years, with some due to be published later this year. The final report will be available in early 2019.
How the Tsunami Simulator Works
The Tsunami Simulator works on the principle of a pneumatic system with a pump, similar to that used for some large leisure or surfing pools. Other tsunami simulators use paddle systems which cannot generate waves of such long duration, or pumped systems that do not propagate the wave over the coastal slope.
In this system, an air pump ‘sucks’ water from the test flume up into the Tsunami Simulator tank. That simulates the water retreat of a ‘trough-led’ tsunami, as seen when the Indian Ocean Tsunami hit Thailand in 2004. Next, the air control valve is opened (under computer control) to allow water inside the tank to fall, thus generating the ‘elevated wave’ or crest of the tsunami. The ‘flow-shaper’ at the tank outlet helps water leave smoothly giving good control of the tsunami generated which then propagates down the test flume to the test section, where it impacts on sea defence structures and/or model buildings.
Source: HR Wallingford