Fails to apply initial conditions for deformable wall simulation

[Vijay Vedula]

Hi,

I followed steps in the documentation for deformable wall simulations for cylinder model with steady inflow and RCR boundary condition at the outlet. I tried to apply steady state rigid wall solution as initial condition for the deformable wall simulation. However, it looks like the initial condition is not properly applied and the solution starts from zero (see attached results). In fact, SimVascular complains for not providing any Initial Pressure or Initial Velocity values in the Basic Parameters tab even after loading the IC File. The presolver script also does not show any indication that the IC File is loaded.

Thanks,
Vijay

Rigid wall solution:

Rigid wall solution at steady state

rigid_wall_flow_00200.png (184.86 KiB) Viewed 312 times

Basic Parameters settings for Deformable Wall simulation:

Parameters settings for deformable wall simulation

deform_wall_SV_IC_settings.png (191.41 KiB) Viewed 312 times

Presolver script:
mesh_and_adjncy_vtu mesh-complete/mesh-complete.mesh.vtu
set_surface_id_vtp mesh-complete/mesh-complete.exterior.vtp 1
set_surface_id_vtp mesh-complete/mesh-surfaces/inlet.vtp 2
set_surface_id_vtp mesh-complete/mesh-surfaces/outlet.vtp 3
fluid_density 1.06
fluid_viscosity 0.04
initial_pressure 0
initial_velocity 0.000 0.000 0.000
prescribed_velocities_vtp mesh-complete/mesh-surfaces/inlet.vtp
bct_analytical_shape parabolic
bct_period 1.000000
bct_point_number 2
bct_fourier_mode_number 10
bct_create mesh-complete/mesh-surfaces/inlet.vtp inlet.flow
bct_write_dat bct.dat
bct_write_vtp bct.vtp
pressure_vtp mesh-complete/mesh-surfaces/outlet.vtp 0
deformable_wall_vtp mesh-complete/walls_combined.vtp
deformable_thickness 0.2
deformable_E 4000000
deformable_nu 0.5
deformable_kcons 0.833333
deformable_pressure 133313.29
deformable_solve_displacements
wall_displacements_write_vtp displacement.vtp
write_geombc geombc.dat.1
append_displacements restart.0.1


Deformable wall solution at ntime = 0:

Deformable wall solution at ntime = 0

deform_wall_flow_00000.png (142.14 KiB) Viewed 312 times

Deformable wall solution at ntime = 1:

Deformable wall solution at ntime = 1

deform_wall_flow_00001.png (167.1 KiB) Viewed 312 times

[Weiguang Yang]

Assume the restart file for the last step in a rigid simulation is restart.100.0. Copy it to your current simulation dir. and rename it as restart.0.1
In your svpre file, remove "initial_pressure 0" and "initial_velocity 0.000 0.000 0.000".
Rerun the presolver script in the command line by typing "svpre xxxx.svpre"
In this way, the initial values are not 0 everywhere.

[Vijay Vedula]

Thanks Weiguang. Will file an issue on github. In the meantime, I think a short note could be added in the Documentation so others are aware of the issue.

[Vijay Vedula]

UPDATE: I tried to load the initial condition file for a rigid wall simulation and it worked as expected. So the issue is with initializing deformable wall simulation by loading an IC file.