Concentric Cylinders in the Comsol Eulerian Model
 

Hello everyone
The Eulerian model in Comsol is used in the simulation, which focuses on cutting transport. Two concentric cylinders are present. The outer one is fixed, while the inner one revolves. Between these cylinders, fluid flows.
In its mixture concept, a "rotating shaft" can be used to replicate it. However, the Euler model must be applied due to the fluid-solid's disparate densities.
However, unlike other models, the Euler model lacks a "rotating shaft" or "moving wall" that would cause a wall to revolve. So, if you know anything about Comsol, could you please help me with this?

Many thanks.