Publication at Faculty of Mathematics and Physics |

2018

We consider a diffuse interface model for the phase separation of an incompressible and isothermal non-Newtonian binary fluid mixture in three dimensions. The averaged velocity u is governed by a Navier-Stokes system with a shear dependent viscosity controlled by a power p > 2.

This system is nonlinearly coupled through the Korteweg force with a convective nonlocal Cahn-Hilliard equation for the order parameter phi, that is, the (relative) concentration difference of the two components. The resulting equations are endowed with the no-slip boundary condition for is and the no-flux boundary condition for the chemical potential mu.

The latter variable is the functional derivative of a nonlocal and nonconvex Ginzburg-Landau type functional which accounts for the presence of two phases. We first prove the existence of a weak solution in the case p >= 11/5.

Then we extend some previous results on time regularity and uniqueness if p > 11/5.