We have been using an explicit coupling of a third party solver called blastFOAM and a FEA solver until recently. Our recent attempts to switch to implicit coupling resulted in some fatal errors (see image below) at the very beginning of the coupled run. Upon looking further, I realized that the error happens inside the ‘writeCheckPoint()’ routine in the file Adapter.C of the OpenFOAM adapter. Specifically, it happens when the surface scalar fields are being stored as part of checkpointing.
I have contacted the blastFOAM support team regarding this and asked if/whether blastFOAM follows the same structure as the official OpenFOAM solvers. The response I received is that the use of fields are all the same, but typically there are no implicit matrices solved. They are also wondering what is needed to implement implicit coupling? Unfortunately, I am not familiar with OpenFOAM code structure and do not know how to advise them on what changes are needed to be able to support implicit couplings. Obviously, I know that the solver needs to store checkpoints of the state but what is not clear to me is if/whether that is done by making a call to an API in the OpenFOAM library? If yes, what would that be?
In summary, are there instructions somewhere that a third party solver like blastFOAM must follow to be able to support implicit couplings through the standard OF adapter? Any response would be appreciated.
Thanks in advance,