An interview with the 2012 Batchelor Prize winner – Detlef Lohse
The following is a Q&A held with Professor Detlef Lohse after he was presented with the 2012 Batchelor Prize at the International Congress on Theoretical and Applied Mechanics 2012
Q: What was it that attracted you to Fluid Mechanics research initially, and is it the same thing that motivates you now?
A: My master thesis was in theoretical high energy physics. When looking for a subject for my PhD thesis, I clearly wanted to work in a field with more interaction between theory and experiment. After I had met Siegfried Grossmann at the University of Marburg who was working on the theory of turbulence it was immediately clear to me that I wanted to work with him on that subject. We used theoretical and numerical methods from statistical physics and nonlinear dynamics to account for experimentally observed phenomena and I learnt tremendously. Only later, during my time as a postdoc in Chicago, I moved towards more traditional fluid dynamics, working on bubble dynamics in the context of single bubble sonoluminescence. The first class I attended in fluid dynamics in fact was the one I taught myself at the University of Twente. There I more and more discovered how nice it is that our field has a great application perspective. Out of our fundamental work various applications have popped up, often not foreseen at all. Vice versa, problems and obstacles in industry have often led us to beautiful fundamental questions in fluid dynamics. I find this close interplay very motivating and intriguing.
Q: In accepting the George Batchelor Prize you paid tribute to the rest of your Physics of Fluids team at Twente. Could you say something about the approach of the team and why you think it has been so successful?
A: Our group is really complementary: Experimental, theoretical, and numerical experience and expertise in constructing and building setups is all necessary in fluid dynamics and our approach is really distinguished by a close combination of all of these methods. This clearly helped considerably. And I have been blessed by being able to work with great colleagues, postdocs, PhD students, master students, and staff, who were all fully devoted to fluid dynamics and science.
Q: If you had to choose, which single piece of research are you most proud of?
A: Probably our work on Rayleigh-Benard convection. In the mid-90s, the subject of heat transfer in thermal convection was considered kind of closed, at least in the physics community. But some inconsistencies had been put under the rug or ignored. Based on the Boussinesq equations and on the idea to split the dissipation rates into bulk and boundary layer contributions, we could account for the heat transfer and the degree of turbulence as a function of the control parameters and make quantitative predictions for unexplored domains in the parameter space, which later turned out to be correct, including the onset of the so-called ultimate regime, where the boundary layers become fully turbulent. It was only this year – 10 years after our prediction – that Guenter Ahlers and co-workers confirmed this prediction quantitatively.
Q: Do you have any advice for a young scientist entering fluid mechanics now?
A: Take the opportunities of the field which allows for doing both experiment, theory, and numerics: I think that fluid dynamics is an excellent field for educating scientists, as one can learn a lot from this combined approach, rather than being only a tiny wheel in a huge endeavor in which the contributors do not have an overview over the project as a whole. The field is also extremely rich, from the nanoscale to the astroscale, from fundamental questions to applied ones, and thus offers great opportunities for the young scientists.
Q: And finally, I have to ask: what is your favourite fluid?
A: That is easy to answer: water. It is one of the most interesting fluids with extremely rich phenomenology – think e.g. of the density of ice being smaller than that of liquid water or of surface nanobubbles which seem to only form in water and not in other liquids. And finally: it tastes very good.