[KingKraut]

Dear all,

I am looking for a way to reduce the output file number of an OpenFOAM simulation.

The simulations are performed with a custom solver based on the pisoFoam solver. We are interested in the time-dependent evolution of a periodic flow through a branching vessel geometry. For following computations of particle transport (concentrations) in this 3D-model we need to write the flux field with a sufficient accuracy of ~0.1 ms.
In order not to produce enormous amounts of file numbers, we would like to reduce the output in the way that the written phi field is not stored in a separate file for each timestep in the appropriate folder. We would rather like to append the computed fields (phi, p, U, ...) for each timestep to the file with the fields of the previous timesteps. Thus instead of producing a file for each timestep the file would be appended with the field of the next time step, creating an ever-growing file containing all the time-steps of the simulation.

I have looked into the solver codes and particularly the createFields.h file and the contained IOobjects, however I have not yet managed to implement this change.
Can anyone help me with this issue or has an idea how to tackel this?
Or in any case do you consider this feasible or reasonable at all within the framework of OpenFOAM?

Any help, advice or general comments and opinions on this topic are highly appreciated. At the moment I am myself not so sure if this could possibly work this way or if this is a wise approach to the problem at all.

Thanks a lot for anybody looking into this!!
Johannes


PS: Any other ideas on how to reduce the output file number of such a case are very welcome, too!!!

Edit: For example if there is a possibility to keep the computed fields of every timestep (not deltaT but the writeInterval) in-memory rather than writing them on disk every writeInterval, this could be an alternative, too, I think.
Thanks

[kebsiali]

hello

I don't know if this is interesting to you or not
but why don't you use utiliteies like adding a probe at some point or line and having your variables printed to a single file as a vector or table

many utilities like these already exist and can be turned on from within controlDict

another way is to create your own utility which would write out the data you want at a part or whole of the domain, in which case you will have to understand the databases available with OpenFoam (the way the tables are written dynamically from every processor using mpi)
but again if you try to know how those utilities were created you can adapt a new one to your own needs