why is sub_ + eqname the prefix of petsc solver?
I find counter-intuitive that the prefix of PETSc solvers used by OpenFOAM is sub_eqname. Why not foam_eqname?
If I use blockjacobi as PC, the prefix for the subsolvers will be sub_T_sub_
for the basic/laplacianFoam/flange case
I would change "sub_" with "foam_" here https://develop.openfoam.com/modules/external-solver/-/blob/develop/src/petsc4Foam/solvers/petscSolver.C#L102