Speaker: Susumu Goto (Osaka Univ.)

Datte: Feb. 8th, 16:00-

Style: Webinar

Title: Progress and issues in fluid turbulence research

Abstratct:

In this talk, I will show the recent progress of our understanding of fluid turbulence. (i) Numerical simulations of turbulent flows at high enough Reynolds numbers have revealed the concrete picture of the hierarchy of coherent eddies and their sustaining mechanism [1-3]. (ii) The revealed picture of turbulence explains the physics of the energy cascade, which gives the basis of the small-scale universality of turbulence. (iii) The picture, however, casts some doubt on the classical view of the small-scale energy balance and forces us to modify the energy dissipation law. (iv) The picture also helps us to develop mathematical arguments on the regularity of the solutions of the Navier-Stokes equations. I will also show the remaining issues and near-future directions of the study of fluid turbulence.

[1] Goto, Saito and Kawahara, Phys. Rev. Fluids 2 (2017) 064603.

[2] Motoori and Goto, J. Fluid Mech. 865 (2019) 1085.

[3] Motoori and Goto, J. Fluid Mech. 911 (2021) A27.