Re: read a list of point in a python script to define a set of points with Dirichlet boundary conditions (follow up)

[Konstantinos Poulios]

Dear Anne-Cecile

In a first look it seems correct for homogeneous Dirichlet condition.

For non homogeneous Dirichlet conditions you do not need the partial mesh_fem, just define

mfpb = gf.MeshFem(meshb, 1)

mfpb.set_classical_fem(press_fem_order)

but then you need to define and use a multiplier variable in the model:

md.add_initialized_data("p_atm", ....)

md.add_fem_variable('p', mfpb)

md.add_filtered_fem_variable('multp', mfpb, DPB)

md.add_linear_generic_assembly_brick(mim, "(p-p_atm)*multp", DPB)

You can see a similar example here:

https://git.savannah.nongnu.org/cgit/getfem.git/tree/contrib/continuum_mechanics/plasticity_finite_strain_linear_hardening_tension_3D.py

BR

Kostas

On Thu, Nov 18, 2021 at 9:16 PM Lesage,Anne Cecile J <AJLesage@mdanderson.org> wrote:

Dear all

 

If I want to define a set of points with Dirichlet boundary conditions on a scalar unknown (pressure), are the following python script lines correct (using numpy here)?

 

import numpy as np

 

DPB = 2  # dirichlet on pressure brain

print('Read DIRICHLET boundary condition cranio');

# read dirichlet conditions on pressure

filecranio = open('craniopdir.txt', 'r') # 'r' = read

pidcranio = np.loadtxt(filecranio,dtype=int)

#print(pidcranio)

filecranio.close()

fcranio=meshb.faces_from_pid(pidcranio)

meshb.set_region(DPB,fcranio)

 

 

mfpb_ = gf.MeshFem(meshb, 1)

mfpb_.set_classical_fem(press_fem_order)

keptdofs = np.arange(mfpb_.nbdof())

keptdofs = np.setdiff1d(keptdofs, mfpb_.basic_dof_on_region(DPB))

mfpb = gf.MeshFem("partial", mfpb_, keptdofs)

 

How to set up that on these faces/nodes the pressure is non zero (p0= atmospheric pressure)?

 

Thank you

Regards

Anne-Cecile

 

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