Colloquium: Is turbulence a critical phenomenon?
An interesting talk on turbulence will be given on Tuesday 11. August by Nigel Goldenfeld. This time it is the Department of Physics' Colloquium and will be held at Store Fys. Aud. Fysikkbyggningen.
TITLE: Is turbulence a critical phenomenon?
SPEAKER: Nigel Goldenfeld
ABSTRACT: Are fluid turbulence and critical phenomena analogous to one another? In this talk, I try to emulate the pattern of discovery which led to the solution of the phase transition problem, and show how critical scaling ideas lead to the prediction of a novel scaling law --- a manifestation of what I term roughness-induced criticality.
This scaling law is verified by analyzing experimental data on turbulent pipe flows, taken by Nikuradze in 1933.
The scaling law arises naturally from a connection between the small-scale velocity fluctuations in turbulence and the large-scale macroscopic flow properties such as friction.
This connection is a type of non-equilibrium fluctuation-dissipation theorem, and has been tested by direct numerical simulations and experiments on two-dimensional turbulent flows in soap films.
These ideas refine the notion of what it would mean to have a "complete solution to the problem of turbulence".