On Wed, 11 Apr 2018, 서승진 wrote:

1) In visualization, I used paraview and open out_2.e (in introduction_ex4).

The paraview displayed the white box. I think that this is mesh for the example.

However, paraview didn't displayed the solution distribution (colored box).

Is the problem is come from the absence of post-processing in the example?

Did you tell paraview to display the solution distribution?

When I first open out_2.e in paraview 5.0.1, it displays nothing.

When I then click on the Properties->Variables->u checkbox and hit
Apply, it displays a white box (the domain for the example).

When I then change from "vtkBlockColors" to "u" in the active variable
controls toolbar, it displays a box colored by the solution.

I understood that Libmesh examples use Dirichlet condition, and the part to set 
boundary condition is;

std::set<boundary_id_type> boundary_ids;
DirichletBoundary dirichlet_bc(boundary_ids, variables, exact_solution_object);

However, I couldn't find the part to set the initial value of u_var and value 
of boundary condition for each boundary.ids...

How I can set the value of initial condition and boundary conditions?

"exact_solution_object" in the above code is the functor which returns
boundary condition values.

Initial condition values are typically set with
System::project_solution().  See transient_ex1.C for an example.
3) In mailing list, some people mentioned about the example which
contain Neumann boundary condition with penalty method,

This sounds confused.  The penalty method sets a Robin boundary
condition which is closely related to a desired Dirichlet boundary
condition, it's not for Neumann boundary conditions.

so I've searched the example in Libmesh, but I couldn't find. Is
there no neumann B.C. example in Libmesh?

systems_of_equations_ex2.C, if you modify it to use the
set_stagnation_bcs() function, has a homogeneous Neumann outflow
condition. fem_system_ex4.C has a homogeneous Neumann condition on one

But homogeneous Neumann in most finite element formulations means "do
nothing", so if you have a heterogeneous Neumann boundary you probably
still want an example... let's see.

miscellaneous_ex9.C uses a constant Neumann flux = 1 on one domain side.

systems_of_equations_ex4.C (and _ex5.C, and _ex6.C...) use a constant
Neumann traction on one side.

Thanks for reading my email.

For your answer, I successfully installed the libmesh.

You're welcome.

You should probably join and send future emails to libmesh-users,
though; that way they might not languish without reply quite as long
when I'm busy.
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
Libmesh-users mailing list

Reply via email to