3. Defects associated with multilayer flow

3.1 Non-uniformities

When observing bilayer flow in a channel of constant cross-section, the interface between the two polymers A and B changes between the inlet and outlet cross-sections.

It undergoes a regular transformation that maintains a clear and precise boundary between the two polymers. This transformation results from the superposition of the following two phenomena:

• Coating or encapsulation phenomenon due to the difference in viscosity of the two polymers (figure 3...