I used this tutorial some times back to solve the Navier Stokes equation and it worked very well.
However, looks like they have made some small modifications and the code, from dolfinx.plot import vtk_mesh gives the following error:

---------------------------------------------------------------------------
ImportError Traceback (most recent call last)
Input In [1], in <cell line: 10>()
8 from dolfinx.io import VTXWriter
9 from dolfinx.mesh import create_unit_square
---> 10 from dolfinx.plot import vtk_mesh
11 from ufl import (FacetNormal, FiniteElement, Identity, TestFunction, TrialFunction, VectorElement,
12 div, dot, ds, dx, inner, lhs, nabla_grad, rhs, sym)
14 mesh = create_unit_square(MPI.COMM_WORLD, 10, 10)
ImportError: cannot import name 'vtk_mesh' from 'dolfinx.plot' (/usr/local/dolfinx-real/lib/python3.10/dist-packages/dolfinx/plot.py)

Earlier, it was written as: from dolfinx.plot import create_vtk_mesh and there wasn’t any issue with that.
Appreciate your comments on this.

Hi @dokken do you know whether the variational formulation of this Navier Stokes Equation has also changed. Because, in my previous code I have L2 = form(dot(nabla_grad(p_n), nabla_grad(q))*dx - (1/k)*div(u_)*q*dx)
and

Phew. Thanks for pointing out. I also had my solution blowing up because of this missing rho.
May I know whether you have made any more changes to the NS solver?