Continuum mechanics- open questions?

[MathematicalPhysicist]

what are the open and still not yet answered problems in continuum mechanics as of today?
i reackon navier-stokes equations solutions is something that is related to the issue, right?

 

[arildno]

Well, the whole messy issue of turbulence might well be considered an open issue. It is anyhow a very active research area.

 

[PerennialII]

On materials side, in their constitutive modeling, one of the trends making progress seems to be tighter multiscale linking. For example, constitutive models of continuum mechanics are fed by & coupled to quantum and statistical mechanics and everything in between, areas of continuum mechanics like fracture mechanics, damage mechanics etc. are going strong and developing (and benefitting lots from this, although there is a lot of research starting only from micro/nano up without the couplings).

 

[arildno]

Another important research area is multiple phase flow.

 

[MathematicalPhysicist]

Another important research area is multiple phase flow.

does this mean that gases and liquids change phases into one another and you can't tell the difference or is it something competely different from what i descrbied.
please, do elaborate arlidno.