boulder impact

Ireland and Great Britain are continuously affected by storms created in the Atlantic Ocean, and the waves whipped up by these storms can transport energy great distances. The movement of coastal boulders can help us to infer how this energy is transferred to land, helping us make decisions about our changing coastlines. In October 2021, the first work from HIGHWAVE’s Breaking Wave Loads work package was published in the Journal of Fluid Mechanics. In the published article, we describe our laboratory experiments in which we recorded the acceleration and pressure on a model boulder when it was struck and moved by breaking waves of various crest shapes.

Before the HIGHWAVE project started, a fieldwork investigation recorded the position of boulders before and after the winter of 2013-2014. The research found that boulders sitting on the cliffs of the Irish West coast and weighing more than 200 tonnes had been moved dozens of meters. Later, in a laboratory at Queen’s University Belfast, video was recorded of model boulders being moved as waves created in the wave tank came over the top of their platform and struck them. The scaled-down waves in the laboratory were representative of those created by a strong storm in the Atlantic. Along with a multitude of other publications, these two pieces of research conclusively showed that it’s possible for waves created by Atlantic storms to move boulders heavier than 200 tonnes, something that had previously been debatable. Now, our own research has made a further step forward in understanding exactly how the type of breaking wave affects boulder movement.

In our experiments, undertaken at École Centrale de Marseille with Dr. Kimmoun, we measured the acceleration, pressure, and movement of a model boulder as it was struck by a single breaking wave in the laboratory. The scaled-down boulder was 8 kg and sat on a 20 cm high platform which was representative of a 216 tonne boulder on a 7.5 m platform in real life. By changing the wave creation method between each test, we were able to change the shape of the wave crest while keeping its energy the same. We found that the boulder experienced both slow and low accelerations as well as very quick and high accelerations, depending on the shape of the wave. The boulder moved the most when the top of the breaking wave had nearly – but not quite – fallen forward to create a barrel shape.

In our next boulder-wave impact experiments, we hope to find out how important the shape of the wave is compared to the wave’s height when it hits the boulder. There are many environmental characteristics that can affect the way that real boulders move. Therefore, slow, steady, and scientific progress is the way forward to confidently answer which are the most important and why.

Read the full open access article here.

The PhD thesis completed in 2019 by James Steer, a post-doctoral research fellow in HIGHWAVE, has been selected by the UK Fluids Network (UKFN) to receive their annual thesis prize. The UKFN is an Engineering and Physical Sciences Research Council funded network of academic and industrial research groups in the UK. After votes from the judges were tallied, the scores of James and two others were tied, meaning each will receive the £200 prize. The entire HIGHWAVE team extend their congratualtion to James and are delighted that he has been recognised for his work. A summary of James' work can be found on the HIGHWAVE website, here, and his thesis can be found in The University of Edinburgh archive, here. The award was been announced by the UKFN on their website and by his alma mater, The University of Edinburgh

HIGHWAVE involves a lot of numerical simulations of nonlinear water waves. HIGHWAVE was successful with its PRACE DECI 16 application. The project has been given 3M core-hours. It will start in the summer of 2020 and will last for one year. 

Prof. Dias will co-chair the European Fluid Mechanics and Turbulence Conference (EFMTC2021) at ETH Zurich from June 20-24, 2021.

Due to the COVID-19 pandemic the EUROMECH council decided to combine the 13th European Fluid Mechanics Conference (EFMC13) and the 18th European Turbulence Conference (ETC18). ETC18 was originally supposed to take place in Dublin in August 2021.

shareGeoScienceOnline

Last week the European Geoscience Union (EGU) gathered for its annual conference. Though not in its beautiful springtime home of Vienna, the conference persevered through an online sharing platform. This was made freely available to everyone (no fees/reimbursed fees for presenters and no attendance fee), with many kudos - as seen on Twitter - given to organisers for such broad accessibility for attendees.

The schedule was kept as originally intended, with a separate online space for each session. Authors submitted a file displaying their research, be it a video presentation, a slide show document, or a figure. Authors representing their displayed research attended a text-based e-session chat and could give a brief synopsis of their presentation, afterwhich attendees addressed questions or comments to the authors. There were over 700 sessions and more than 200,000 messages!

The sixth Annual Irish SIAM Student Chapter Conference was held at NUI Galway on 6 December 2019. Clement Calvino, Daniel Giles and Tatjana Kokina, PhD students and members of the Wave Group of School of Mathematics and Statistics, UCD, attended the conference.

It was a full day, with plenary lectures and presentations from PhD students from all over Ireland. The range of topics was very broad and everyone got to see all possible applications of mathematics from social networks and the dark web, to oceans and protein adsorption.

SIAM collage final

The third and last HIGHWAVE public meeting explaining the 5-year project (2019-2024) took place on Inis Oírr on 27 November 2019. It was well attended despite bad weather over the Aran Islands for the past couple of days. Professor Dias and Research Engineer Arnaud Disant were asked a lot of questions on wave breaking, environmental issues, instrumentation but also on the future of the project after 2024. 

IMG 1077

Professor Frédéric Dias delivered today on Inis Meáin the second talk on extreme wave generation and wave breaking related to the HIGHWAVE project on the Aran Islands. The presentation took place at Halla Naomh Eoin. The local fishing community was represented and the support of Ciara (Bainisteoir, Comhlacht Forbartha Inis Meáin) is kindly acknowledged. The project is already receiving unconditional support from the local community. The project will return benefits in kind, such as data which can be used to backup grant applications. Regular progress meetings will be organised on Inis Meáin.