Quick questions:

1. Which OpenFOAM version/variant/fork are you using?
2. Have you looked at the tutorial cases for the version you are using?

For example, at least since OpenFOAM 2.2 to 6, the convention for multi-regions is still roughly the same, you run decomposePar with the option "-allRegions". For example:

• 2.2.x: https://github.com/OpenFOAM/OpenFOAM...nHeater/Allrun
• 6: https://github.com/OpenFOAM/OpenFOAM...nHeater/Allrun

Hi

try to use decomposePar -allRegion insted of "decomposPar"

good luck