About 60 years ago it was discovered that one can bring macroscopic
changes in the turbulent flow of fluids by adding just a minute amount
of polymers. Since then the phenomenon found many applications where
the most famous one is the drag reduction: polymers help to
lower the losses in the fluids' transfer in pipelines significantly.
The complete understanding of the polymers' influence on the
flow is still lacking. One thing is clear: this is a transition
phenomenon where polymers are negligible when turbulence is not sufficiently strong and become important otherwise. In this talk I will describe
recent progress understanding the transition. |