Hello everybody,
I try to run the code below:
from fenics import *
T =Constant(350)
P = 200000 #pressure in [Pa]
R = Constant(8.314462176) # [J*mol/K] universal gas constant
u_in = 0.8
u_out= 0.1
xml_file = "02Mesh.xml"
mesh = Mesh(xml_file)
fd = MeshFunction('size_t', mesh, "02Mesh_facet_region.xml");
materials = MeshFunction('size_t', mesh, "02Mesh_physical_region.xml");
V = FunctionSpace(mesh, 'P', 2)
bc1 = DirichletBC(V, Constant(u_in), fd, 101)
bc2 = DirichletBC(V, Constant(u_out), fd, 202)
bc = [bc1, bc2]
u = Function(V)
v = TestFunction(V)
dx = Measure('dx', domain=mesh, subdomain_id=3)
EffectiveDiffO2 = 0.001
# Define variational problem
F = EffectiveDiffO2*dot(grad(u), grad(v))*dx \
- (u*100)*v*dx
solve(F==0, u, bc)
but unfortunately, I got this error:
*** -------------------------------------------------------------------------
*** DOLFIN encountered an error. If you are not able to resolve this issue
*** using the information listed below, you can ask for help at
***
*** fenics-support@googlegroups.com
***
*** Remember to include the error message listed below and, if possible,
*** include a *minimal* running example to reproduce the error.
***
*** -------------------------------------------------------------------------
*** Error: Unable to solve nonlinear system with NewtonSolver.
*** Reason: Newton solver did not converge because maximum number of iterations reached.
*** Where: This error was encountered inside NewtonSolver.cpp.
*** Process: 0
***
*** DOLFIN version: 2019.2.0.dev0
*** Git changeset: unknown
It would be great if somebody can suggest that where is the problem.