Powered by OpenAIRE graph
Found an issue? Give us feedback

Danish Hydraulic Institute

Danish Hydraulic Institute

2 Projects, page 1 of 1
  • Funder: UK Research and Innovation Project Code: EP/F030975/1
    Funder Contribution: 430,172 GBP

    The Anaconda is a new concept for wave energy conversion. It is just a rubber tube in the sea, full of water, closed at both ends, anchored head to waves. It is squeezed or enlarged locally by pressure variations that run along its length due to the waves. Squeezing a water-filled rubber tube starts a bulge wave running. The bulge wave travels at a speed that is determined by the geometry and material properties of the tube. The Anaconda is designed so that its bulge wave speed is close to the speed of the water waves above. In these conditions the bulges grow as they travel along the tube, gathering wave energy. Inside the tube, the bulge waves are accompanied by a periodically reversing flow. One way of extracting power from the Anaconda is to use a pair of duck-bill valves to convert this into a rectified flow past a turbine between high and low pressure reservoirs. We have proved the concept of the Anaconda at a scale of about 1:85 in a laboratory wave flume. At this scale a large part of the converted wave energy is lost in heating up the thin wall rubber from which the tube is made, and in the turbulent flow through the valves. Nevertheless, the model absorbed all of the incident wave power over a front equal in width to as much as 5 times its diameter. A power take-off system accounted for about 20% of this, corresponding to more than 250kW for a 7m diameter Anaconda, 150m long, in waves 2m high. At larger scale, energy losses would be much less significant and the proportion of useful power conversion much higher. A device rated at 1MW would contain about 100 tonnes of rubber, making the Anaconda an exceptionally light wave energy converter for its power.When it comes to predictions, the Anaconda is like no other marine vessel or structure. It has some features in common with Pelamis, but it is much more compliant, has many more degrees of freedom, and does not necessarily follow the motion of the water surface. Our mathematical models of it are rather basic, and in many respects are not in very good agreement with laboratory measurements. The aim of this research is to develop a better understanding of the hydrodynamics of the device, and formulate a comprehensive and validated numerical with which to make more reliable estimates of full scale performance. Experiments will be carried out at scales of 1:28 and 1:14, with tubes of diameters 0.25m and 0.50m, at which rubber hysteresis losses will be proportionately much lower than at smaller scale. Three types of experiments are planned, to provide measurements of internal pressures, tube displacements, radiated waves, mooring forces, and absorber power:(1) measurements in still water with bulge waves generated mechanically at one end of the tube, and absorbed at the other,(2) measurements in regular and irregular waves,(3) measurements in extreme waves.The results will provide insights into the mechanics of the device and support the development of a numerical model that will for the first time include the effects of wave radiation and other factors so far neglected. Some features of the work will be relevant to other examples of wave interactions with compliant surfaces.

    more_vert
  • Funder: UK Research and Innovation Project Code: EP/R007349/1
    Funder Contribution: 1,091,730 GBP

    Reliable and comprehensive flood forecasting is crucial to ensure resilient cities and sustainable socio-economic development in a future faced with an unprecedented increase in atmospheric temperature and intensified precipitation. Floodwaters from the areas surrounding a city can heavily affect flood cycle behaviour across urban areas, introducing uncertainties into the forecast that are often non-negligible. However, currently the extent to which we can predict flood hazards is limited, and existing methods cannot for example deal with inter-regional dependencies (e.g. as was seen when floods affected nine different countries across Central and Eastern Europe). Presently in the UK approx. 25% of yearly flood insurance claims are from areas outside the zones forecast to be at flood risk, and annual flood damage costs are already high (approx. £1.5 billion). Also more than 20,000 houses per year continue to be built on floodplains. The need to transform flood forecasting for a range of applications and scales has already been recognised by various parties. The UK Climate Change Risk Assessment 2017 Evidence Report prioritises flooding as the greatest direct climate change related threat for UK cities now and in the future, and urges urgent action to be taken, including the development of new solutions over the next 5 years. The hydraulic software industry and consultancy firms have expressed a desire for more reliable and sophisticated flood forecasting approaches, which can also reduce the manual labour required. In addition, mathematics and engineering research communities are still searching for forecasting models that are joined-up, reliable and efficient, as well as versatile and adaptable. To address this need, 'Multi-Wavelets' technology will be employed in this fellowship with a view to transforming flood forecasting routines from a disparate set of activities into a unified automatic framework. The applicant's vision is to exploit the innate capability of Multi-Wavelets technology to reformulate flood forecasting methods by providing a smart modelling foundation for the delivery of timely and accurate flood maps, alongside statistically quantified uncertainties. This research presents a unique opportunity for the applicant, UK academia and UK industry, to establish a world leading capability in a nascent field while addressing Living With Environmental Change (LWEC) priorities for improved forecasting of environmental change. The fellowship research will stimulate the creation of new software infrastructure capable of significantly improving our flood forecasting ability across length scales and under multiple uncertainties, helping us to better design infrastructure against flood risk and to plan for the consequences.

    more_vert

Do the share buttons not appear? Please make sure, any blocking addon is disabled, and then reload the page.

Content report
No reports available
Funder report
No option selected
arrow_drop_down

Do you wish to download a CSV file? Note that this process may take a while.

There was an error in csv downloading. Please try again later.