Studies of fluid dynamics: turbulence

Studies of fluid dynamics: turbulence


Whoever stands on a riverbank can notice how
water moves according to a random, apparently irregular motion, generating vortexes of various
form and size. The same happens when we stretch out on a
lawn to watch the clouds in a windy day. Water and air are fluids. When a fluid acts chaotically and irregularly,
we call it a turbulence. Between the Wars, the majority of aeronautical
companies built some hypogean systems to be able to make aircrafts in case of a time of
war. They mostly made tunnels through the mountains. The former Caproni industries in Predappio
represent this kind of industry and the tunnels they made stand as an ideal place to host
a facility apt to study turbulence. Ciclope was born in 2015, right inside Caproni
tunnels. The idea was to create a research facility,
namely a wind tunnel, to be used by different research groups coming from all over the world
to make trials and use the instrumentation at their disposal. There is a very unique facility that becomes
a magnet to bring people, to attract people, to come to do the research and provide answers
for very important open questions: the impact fuel economy and saving energy, safety and
many other aspects, all related to turbolence. Turbulence is often given a negative connotation,
being often associated to typhoons and tornados, i.e. natural disasters. Whenever we travel on a plane, we are used
to hear a voice saying ‘You are kindly requested to fasten your seat belts, as our plane is
passing through an area of turbulence’. In some of his drawings, Leonardo Da Vinci
revealed his keen interest in issues related to turbulence. Then, a number of other famous scientists
have spent plenty of time focusing on this phenomenon. Despite of such a strong commitment, the issue
of turbulence is one of the few problems of physics that are still unsolved. The problem with turbulence is that we do
know equations, but we cannot solve them, nor even by using the most powerful calculators
available worldwide. Therefore, what we usually do in this case
is a trial that, theoretically, may give us the answers we are looking for. In fact, this is a bit harder than that, as
we can surely recreate conditions, in our laboratories, that are similar to the real
ones. Yet, to recreate such conditions does not
mean to be able to do measurements. Therefore, we could develop increasingly smaller
instruments to follow the resulting vortexes – but the matter is we would have to stop
at some point, otherwise we may lose measurement accuracy. The philosophy we adopted in this laboratory
is that of making it larger. This facility is unique also on European level,
but also, I would say, worldwide. It doesn’t exist anywhere else in the world. And it’s very nice to have this facility,
because it makes it possible for European researchers to come and collaborate on turbolence
research. And also I know that have been people also
from outside Europe coming to do experiments in CICLOPE. The laboratory in Predappio is quite unique,
because it is inside a mountain, so the conditions are quite stable. They don’t change, because of temperature,
noise and also they are quite unique, because of the size of the tunnels. The pipes size almost 1 meter. The pipe lenght which is almost a 130 m also. You could not do somewhere else. It is a closed-loop wind tunnel, so we can
say that the air flowing inside the tunnel is always the same. There are systems to keep conditions steady
inside this circuit and, most of all, to create the initial conditions we want. This pipe was aligned with utmost accuracy,
as even a minimum curvature would produce disturbing effects. So, in that way, what could we offer to the
scientific community in the future? Not only turbulent models, but also monitoring
techniques for strength and friction, which are the main cause of consumptions and, consequently,
of emissions. There would be economic and financial advantages,
but also environmental ones. Finally, there would also be new measurement
techniques and new sensors, thanks to the cooperation with other universities and laboratories
with facilities like ours, or working on the same issues. This is a facility that would take many years
to bring all the fruits of the results. I’m sure you know, for example the CERN, near
Ginevre. There are physiscists that had been working
on the same facility for many years and sometimes take 1 or 2 year to produce results. And I think it’s very significant that the
University of Bologna has provided a home for something that can be over big, scientific
and practical impact. These atmospheres can really offer an occasion
to exchange ideas and approaches to work as well, working modes, on a same scientific
issue that can be seen from different points of view here, given the number of people dealing
with the issue, i.e. those involved in the research group, but also given their different
backgrounds – and everything takes place, so to say, here at home. A famous anecdote in our scientific community
has it that Heisenberg, Nobel Prize for Physics in 1932, on his deathbed made a wish to meet
God, to ask Him two questions, the first being ‘Why relativity?’ and the second one ‘Why
turbulence?’. Heisenberg was optimistic about God being
able to answer the first question. Certainly, Ciclope was not born with the ambition
of answering Heisenberg’s question. What we can do, on the other hand, is take
baby steps towards a better comprehension and modelling of this most complicated phenomenon
of physics.

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