I tried to work with diameter of particle about 20-100 microns, but I read here there are a limit because a precision machine issue and just I could work with 124 microns of diameter min in SI units. I changed my problem to CGS units, but I have some questions. In the example of tutorial ErgunTestMPI_cgs, the script Allrun.sh calls to controlDict_cgs_2.2.x and copy in other directory. It is necessary? What is it doing exactly ? .
In the other hand, I took exactly the same case and i converted all the units to cgs system, but the results are not the same as the SI. they are close but not equal. Does anybody knows why i'm watching differences?