Unused Boundary Condition Error while solving coupled PDEs

[DelightE99]

Hi David and Team.
I encountered an issue when trying to solve the coupled PDE equation below

It's a 1D energy equation for a porous gas-solid media and when I implemented the code below, I got the error "unused boundary conditions" and the equation was not solved.

Code

Error

I have searched the documentation to see where the source of error could be or to find a template for the coupled equations, but I haven't found any so far.

I am not sure if I am cascading the PDEs in the right format or if the problem is with the field definition or how I specified the bc's (bc didn't work so I used bc_ops)....

For better context, the boundary conditions at the left/top is Dirichlet for fluid and Neumann for solid and at the right is Neumann for both fluid and solid and I do not know how to implement that.

I would appreciate it if you point me in the right direction on this one. Thanks in advance!

[david-zwicker]

It looks as if you used the wrong syntax for setting the boundary conditions. Generally, the bc_ops argument of the PDE class expects boundary conditions given for each operator. If you want to use the same conditions for all operators in the expression for the evolution rate of a particular field, you can simply use the wildcard symbol * to denote all operators. Consequently, the definition of bc_total in your case should rather read bc_total = {"T_f:*": bc_fluid, "T_s:*": bc_solid}.

By the way, it would help tremendously if you provided the code of an actual example demonstrating the problem instead of screenshots!