Problem to solve a Navier-Stokes problem with a Custom Newton solver in FEniCSx

[dokken]

@Karlosjusus

u_icondition = Function(V)
p_icondition = Function(Q)
u_icondition.interpolate(u_exact)

up_f = dolfinx.fem.locate_dofs_topological(W.sub(0), fdim, up_facets)
wall_f = dolfinx.fem.locate_dofs_topological(W.sub(0), fdim, wall_facets)
down_f = dolfinx.fem.locate_dofs_topological(W.sub(1), fdim, down_facets)

#######################################################################################################################

    # Bounday conditions

bc_u = dirichletbc(u_icondition, up_f)
bc_w = dirichletbc(u_icondition, wall_f)
bc_p = dirichletbc(p_icondition, down_f)

You are not setting your boundary condition correctly, as you are using a mixed finite element. Ref: Incompressible Navier-Stokes with particular scheme & mixed elements FEniCSx - #6 by dokken