P Cvitanović Recurrent solutions and dynamics of turbulent flows, as seen in experiments overheads (Sep 24, 2022 Georgia Tech Math Colloquium - 44 min) |
In the world of moderate, everyday turbulence of fluids flowing across planes and down pipes, a quiet revolution is taking place. Today we routinely compute 'exact coherent structures', numerically precise 3D, fully nonlinear Navier-Stokes solutions: unstable equilibria, traveling waves, and (relative) periodic orbits. Experiments carried out at Georgia Tech (starts at min 24:15 of the video) measure 'exact coherent structures' and trace out their unstable manifolds. What emerges is a dynamical systems theory of low-Reynolds turbulence as a walk among sets of weakly unstable invariant solutions. | |
Turbulence: A tutorial |