I am sharing a few tips and tricks for better OpenFOAM simulations. These are not any new tips I discovered. These are just some which I felt most useful based on my experience.

1. Mesh is the most important aspect - I have spent countless hours fixing issues in other places while the real issue was with my mesh. As a thumb rule, make sure the mesh has: no non-orthogonality issues, low aspect ratio cells, no refinement zones in the region with high gradients

2. Always start with a coarse mesh - fix your problems fast!

3. OpenFOAM tutorial cases are not fine tuned, so don't use them blindly for your case. Check the boundary conditions used by tutorial in Doxygen (or the header file in src) and ensure that the right parameters are chosen for your model physics.
Eg: totalPressure BC uses rho=none for incompressible and rho=rho for compressible subsonic.

4. For internal flow, ensure that the mass flux is stable at the inlet and outlet. For statistically stationary flows, the average mass flux should be constant/ periodic.


<more to be added as I keep learning >