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Fête de la science 2017: Voyages(s) - mouvement, territoire, migration

COMUE Lille Nord de France, CNRS Nord - Pas de Calais et Picardie, Université de Lille

Gare Saint Sauveur, Lille
- October 7 and 8, 2017


Stand Voyage dans la turbulence
Stefano Berti and Enrico Calzavarini


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.

More details in our poster [
pdf]




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 des Sciences, Villeneuve d'Ascq, for lending us the wind tunnel and P. Berti for the cars.
 
Enrico 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.

One essential feature of fluid turbulence is the presence of vortices. This movie shows a single vortex in a bottle.






Movie of interacting vortices in a soap film.


Another movie of turbulence in a soap film.