Far from being an
exception, fluid turbulence is a widely spread phenomenon, with impacts
on several technical and scientific problems: from energy production to
the performance of transportation means, climate, the
distribution of biological species in the environment, or planet
formation. Due to its spatially multiscale and temporally irregular
character, turbulence is a complex phenomenon. Its detailed
comprehension still represents a major open problem of classical
physics. Some important advances on the understanding of its basic
mechanisms have been possible thanks to statistical approaches
developed in the twentieth century. At the core of this theory lies the
concept of interactions among eddies (or vortices) of different sizes
and the related exchanges of energy. These determine the essential
characteristics of the flow, particularly its fractal (i.e.
self-similar) nature and the distribution of energy among eddies.
Our stand. Using a table wind
tunnel we showed the turbulence generated behind some vehicles using
water vapor droplets to visualize the flow. We thank Forum départemental
Villeneuve d'Ascq, for lending us the wind tunnel and P. Berti for the
illustrating the fractal
nature of turbulence by an analogy with the geometrical properties of romanesco broccoli.
A movie showing the
laminar and turbulent flows, respectively before and after a car in the
table wind tunnel.
of fluid turbulence is the presence of vortices. This movie shows a
single vortex in a bottle.