A group is studying the scalability of OpenFOAM on different clusters, and for different configurations of OpenFOAM. The outcome of this work will be made public.
We have started using a dropletSplash test-case, developed by Hrvoje Jasak, and it has been run on several clusters. The major finding this far is that OpenFOAM scales linearly as long as the processes are distributed using a round-robin model, where multi-core nodes are not filled-up with processes from the same job. The interconnect is not a bottleneck as long as there are approximately 50,000 cells per process.
