[zackzack1]

Hello everyone,
I am new to COMSOL Multiphysics and I am trying to simulate a 2D fluidized bed using the Euler-Euler Model, Turbulent Flow.

The bed initially occupies only part of the total volume (176 [mm] out of 500 [mm] in height), I want to know how I can apply it to the model if possible. I have set the initial value for the volume fraction of the dispersed phase (phid) to 0.352, but I am unsure if this is the correct approach.

When I compute, I am getting an error that says "Undefined value found in the equation residual vector." I have read that this kind of error appears when we have a missing or incomplete Boundary Condition issue, but I am not sure how to fix it.

Thank you for your time and expertise.

Kind regards,
Zack