Error in fluid-fluid interface
 

Hello guys
I just started using Ansys CFX and ran into a problem with a domain interface.
I have been trying to simulate water that flows from a pipe into the atmosphere. For that I defined 2 fluid domains, one with water and the other with air and connected them with a domain interface. The inlet of the waterpipe has a normal speed of 10 m/s and medium turbulence. The walls of the pipe are smooth. The air domain is defined as an opening with medium turbulence.
Both domains use the k-Epsilon Turbulencmodel.
Now when i try to start the solver i get an error saying: ERROR #001100279 has occurred in subroutine ErrAction. Message: Equation subsystem: "Momentum and Mass - 1" has not been found on both sides of interface "Domain Interface 1". Check that you have set consistent physics across all domains that use this interface.
In order to be able to define different fluids for the 2 domains i had to disable constant physics. Could the problem lay there? I already checked the ansys user manual but i couldnt really find anything that would explain this error. I dont really know what to do now. It would be great if somebody could help me.

Yes, your problem is linked to your disabling constant physics. How can an interface work when the equations on both sides of the interface are different?

You need to redo this simulation without constant domain physics. It sounds like a multiphase simulation based on what you have said.

As Glenn pointed out, this is definitely a multiphase simulation using ANSYS CFX vocabulary.

Non-constant physics is for cases where the air, and the water do not interact directly, i.e. they are separated by walls.

Keep in mind that for ANSYS CFX, domains are not modeled phases but regions of space with common physics definitions. If the water flows into another domain where water is not defined, it is an incorrect setup.