Nonzero pressure Navier Stokes

[dokken]

Several things to consider here.

1. Starting from zero fluid flow, with a non-ramped inlet condition will cause an initial pressure wave going from the inlet into the domain. Consider either starting with a ramped inlet condition, or an initial condition that is non-zero (for instance generated with a Stokes solver).
2. Using strong pressure conditions is not something I would advice, see for instance: https://asmedigitalcollection.asme.org/appliedmechanicsreviews/article-abstract/59/3/107/465438/On-Boundary-Conditions-for-Incompressible-Navier
3. Have you tried with a direct solver, rather than gmres and hypre?

@Nick_Rovito

I’m confident in the weak form, we have a similar script in Dolfin 2019 that behaves as expected, but I’m not willing to rule the weak form out as a possibility. I do think the issue lies within how I’m setting up the PETSc matrix system.

If you have a similar setup in legacy FEniCS, could you provide that code as well?