Fluid state cannot be fully initialized

Problem

I was working with a user on initializing an svMultiPhysics fluid simulation state from a 0D simulation; projecting the 0D pressure and velocity to the 3D mesh VTU file and using that in the Initial_pressures_file_path and Initial_velocities_file_path solver XML parameters.

Starting a svMultiPhysics fluid simulation using 0D simulation has almost no effect on results. However, a simulation can be fully initialized and continued no problem from a stFile_last.bin file.

Looking at init_from_bin I see that stFile_last.bin file sets state data for time step unknowns in the 0D domain,velocity, pressure, and acceleration

  bin_file.read((char*)cplBC.xo.data(), cplBC.xo.msize());
  bin_file.read((char*)Yo.data(), Yo.msize());
  bin_file.read((char*)Ao.data(), Ao.msize());

cplBC.xo is used to initialize RCR BC integration. Not using this data is the primary reason the simulation state is not fully initialized.

Solution

One solution is to initialize the RCR BCs using the script written by @taeoukkim to compute a phase-aware initial capacitor pressure for RCR boundary conditions; this will soon be added to https://github.com/SimVascular/svMultiPhysics/tree/main/utilities.

Another solution would be to have the 0D and 1D solvers write RCR state data that can be read in by svMultiPhysics to initialize RCR BCs.

Additional context

Note that the svSolver CFD solver can read in just pressure and velocity data to fully initialize its state.

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