Hi, friends.

Does anyone know anything about drag reduction by polymers in case of the flow in porous medium? (Sure, for turbulent flows it is well known.) Could you give me a reference to experimental results? Any information on numerical simulation using non-Newtonian model would be quite useful, too.

Sergei

I once heard about that such kind of materials can reduce the vortex scale and therefor reduce the frictional drag. And Americans had already apply this idea to their sail ship for sport competition. This question is mainly dealed with non-steady aerodynamics, Good Luck!

Thanks,

What you are talking about is for turbulent flows, while I was asking about flows in porous medium, or for flows in branching pipes like blood vessels at relatively small Reynolds numbers.