Discussion Forum

I have a simple problem where I have one fluid region in motion that I solve for sufficiently long to capture that motion. I then want to bring a second fluid in contact with that with the assumption that the second fluid starts off stagnent and other initial but consistent conditions with the existing region. Internally I've used a parameter to act as a switch to have the second region turn on in geometry, then use a solver with the solution initially primed with the end of the single-region solution. The geomtrey is simple, two rectangles that touch at a side.

The issue I have is that in this two-step approach (solve without the region then, then turn on the region and solve again) requires me to step pretty much through each workflow step - materials, physics, meshing - to make sure the second region is active for each physics mode and BCs are set right, since changing the geometry for the first step (removing the region) messes up the physics settings. It is not impossible to run through all these prior to the second step but it is prone to user error.

I did think about duplicating the physics and using the per-solver settings of which physics were active, but this creates a lot of problems with variable mapping and duplication.

Is there a simplier way of simply having the solver to ignore one domain? Or a different way to set up the problem so that I don't lose all the physics settings when I change the geometry.