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Hi,

I want to update the expression for a time dependent boundary condition for the incompressible solver. I have defined a bc as
<D VAR="u" USERDEFINEDTYPE="TimeDependent" VALUE="A*sin(B*t)" />
<D VAR="v"...>
<D VAR="p"...>
where A and B are parameters I have defined in the <PARAMETERS> section.

After N time steps, I want to update the parameter A. Right now I am using a restart approach. Run nektar for N steps with a value of A. A checkpoint file is written at the end. Then, update the config file with the new value for A and use the checkpoint file as a restart, in order to run another N steps with the new value. This is not the most efficient way though.

I have read about the "Coupling" capability but I think it is not suited for this problem as A is not a flow variable. Also considered using the "Boundary conditions from file" but my case is 2D and this capability is currently only implemented for 3D. I think the only option is to modify the source code. Specifically, add a piece of code in DisContField::v_EvaluateBoundaryConditions that reads the parameter A from a file and then updates the boundary condition. However, I am not exactly sure how to modify the parameter A that has been read from the session file.

Could you please give me some guidance on how to code that?

Thank you.

Regards,
Guillermo