[FreeFlow] No Newton convergence for pressure Dirichlet BCs at high Re

For simple pipe flow, setting Dirichlet BCs for the pressure both at the inlet and outlet works well for low Re. For higher Re, the Newton scheme does not converge anymore.

Setting the inlet BCs to Dirichlet for velocity works.

This should be investigated. Maybe the assumption of

\nabla \mathbf{v} \cdot \mathbf{n} = 0 and \nabla p \cdot \mathbf{n} = 0

used for the pressure BC causes this problem?