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Non-Intermittent Turbulent Flows: The Decimated Navier-Stokes Equation
Samriddhi Sankar Ray - International Centre for Theoretical Sciences, Bengaluru
Jeudi 21/02/2019, 14h00-15h00
SPEC Salle Itzykson, Bât.774, Orme des Merisiers

Séminaire spécialisé


In the last few years the microscopic origins of intermittent behaviour in fully-developed turbulence has been revisited by using the trick of Fourier decimation [Frisch, Pomyalov, Procaccia and Ray, Phys. Rev. Lett. 108, 074501 (2012)]. In particular, the suppression of a finitely small number of triads involved in the non-linear energy cascade has been shown to dramatically reduce the intermittent behaviour associated with high Reynolds number turbulence.
In this talk we will discuss recent results from direct numerical simulations of the three-dimensional Navier-Stokes equation, on a reduced Fourier lattice, and show how the suppression of a few Fourier modes lead to surprises and open questions regarding the origins of irreversibility, chaos and intermittency in fully developed turbulence.
1. U. Frisch, A. Pomyalov, I. Procaccia, and S. S. Ray. Phys. Rev. Lett. 108, 074501 (2012)
2. M. Buzzicotti, L. Biferale, U. Frisch and S. S. Ray. Phys. Rev. E 93, 033109 (2016)
3. M. Buzzicotti, A. Bhatnagar, L. Biferale, A. Lanotte and S. S. Ray. New J. Phys. 18, 113047 (2016)
4. S. S. Ray. Phys. Rev. Fluids (Rapids) 3, 072601(R) (2018).
5. J. R. Picardo and S. S. Ray, ongoing work (2019).



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