“My research could lead to Olympic gold”
- Name: Stig Staghøj Knudsen
- Age: 40
- Education: MSc., Mechanical Engineering, DTU
- Project research field: Fluid-Structure Iinteraction
- Project period: 2021-2023
- Supervisors: Professor Jens Honore Walther (principal supervisor) and Professor Brian Nyvang Legarth, both from DTU Construct
Text: Magnus Stenaa Jensen, Lotte Krull
Photo: Frida Gregersen
My PhD project is about ...
… how to optimize the sailing of the catamaran Nacra 17, which is an Olympic boat class. The boat is a so-called hydrofoil boat, i.e. it has foils which are wings that function underwater and lift the boat’s two hulls above the water surface, so it almost flies over the water. It offers less resistance and thus increased speed. But the higher the boat ‘flies’, the less control you have over it.
There are many ways to adjust the foils. They can be angled differently in the water, and you can distribute the weight on them differently. Weather conditions also affect the sailing as well as taking into account how much the boat moves sideways. Since the foils carry the entire weight of the boat, they will deflect a lot, but without breaking. The deformations affect how the water flows past the foils, which again affects the boat speed.
So finding the optimal way to sail the boat is complex, and that’s the basis for my calculations. So far, most calculations have been relatively simple, but in my research I have combined several complex mathematical models to obtain more precise calculations. Among other things, I have included temporal variation in my model, where more static models have traditionally been used.
Temporal variation is important as this boat type is tremendously dynamic and things happen very quickly.
The research can contribute to ...
… giving the sailors the deciding margins. Only the most talented sailors sail the Nacra 17, so very small margins can be the difference between the gold medal and finishing last. By simulating waves and the impact of wind on the boat, sailors can gain insight into where to optimally position themselves on the boat and how the boat needs to be adjusted if they are to sail as fast as possible without capsizing.
I have created the model in collaboration with Laura Marimon Giovannetti, who in addition to being a researcher is also the coach of the Swedish and Danish Nacra 17 national teams, and she uses knowledge from the model directly in her training.
Although large nations have applied similar methods for a while, it has been an area where we in Denmark have lagged far behind in our development, as there is not much money in sailing.
In the world of research, my work will contribute to using more complicated calculation models in fluid-structure interaction in the future and getting them to work together.
I get new ideas for solutions when I ...
… take a break from work and for example go for a run. Breaks are important because you can get too immersed in your work. Getting away can give you a new perspective and see your work in a new light when you return.
It’s been a great day on the job when ...
… the models work and produce good results. A good result is when you get values that match the measurement results. We have made a few measurements out on the water, but not enough to be used for validation. So we have used experimental data made in a test tank in Sweden. We can set up a lot of advanced simulations, but we need to know if they are calculating correctly. Therefore, we have spent a lot of time validating the models.
I take a break from my work when ...
… I go sailing. I have a small 25-foot sailboat in Brejning Harbour by Vejle Fjord. I have sailed all my life, including competitive sailing. As a sailor, I haven’t benefitted from my research results, as I do not sail a hydrofoil boat. But I have followed the new development of them, and I think it’s exciting that the boats have started flying.
I became a PhD researcher at DTU because ...
… I was able to work intensively with sailboats and fluid-structure interaction. I got the opportunity because Professor Jens Honore Walther at DTU Construct had research funding for a project in the world of sport which had to concern flow. I know Jens from my time as a student, where I wrote my Master's thesis with him as my supervisor.
As a new PhD researcher, I was surprised by ...
… how much historical material is expected in articles and how many small details need to be discussed. There is a level of detail that I find a little exaggerated. I have worked in industry for many years—both as a Bachelor of Engineering and later as a Master of Science in Engineering, so I’m used to projects with short time horizons. The pace is faster in industry, and focus is more on results rather than the history in the field. There were some reviews of my articles in the PhD project, where the feedback told me to write much more about other researchers’ results in the field. Of course, that’s relevant to know, but I think it takes up an incredible amount of space.
The biggest challenge I experience as a PhD researcher is ...
… having the sufficient patience to work on a three-year project where I believe the focus on results should take up more space.
In the future, I will ...
… work in my own consulting company, Staghøj ApS. I’m already well underway. I help companies solve specific tasks and further educate their specialists. My clients include industrial companies that need optimization and flow calculations. One of my strong competences is ship hull optimization, so I continue to work on maritime applications. If I have to do research again, it won’t be full-time.