energy cascade

Energy cascade in turbulent flow is a really interesting topic! In EUROMECH 561, lots of talks were about the energy cascade in isotropic turbulence. Whether turbulence can become 2D or even 1D is in debate. It is very interesting to notice that in rotating, stratified, geophysical flows, when the third direction is confined, the energy can cascade from the small scale towards large scale.

Even though I am still confused about this phenomena, the understanding of Jimenez's 2012 review paper about cascades in wall-bounded turbulence is much better now. This plot shows the kinetic energy and the dissipation for channel flow at Retau=2000. It is clear, at different wall distance, the energy containing and dissipation eddies change the sizes.