Séminaire MACS (Modélisation, Analyse et Calcul Scientifique). Commun ICJ & UMPA.

An analytical study of intermittency in turbulence through Riemann's non-differentiable functions.

par Daniel Eceizabarrena (University of Massachusetts (Amherst))

Europe/Paris
Description
Intermittency is a property observed in turbulence and, 
in some sense, it represents how much real turbulence diverges 
from Kolmogorov's K41 theory. It is usually measured using the 
so-called flatness, based on structure functions in the physical 
space but also on Fourier high-pass filters. 
In experiments, the two approaches often give different 
measurements. After presenting these concepts, I will talk about 
the similarities and differences between these two flatnesses 
from an analytical point of view. To do so, I will compare them 
using Riemann's non-differentiable function, which has been 
related to turbulence, the multifractal formalism and the motion 
of vortex filaments before.
This work follows the trend of "mathematizing" turbulence, 
and is in collaboration with Alexandre Boritchev and 
Victor Vilaça da Rocha.