Skip to content

Particle stress history (Lagrangian_Swarm) gives a NaN first residual on the viscoelastic cylinder benchmark #738

Description

@lmoresi

The fully Lagrangian stress history has not been run on the cylinder benchmark before, and it does not run now: with Lagrangian_Swarm (cells or nodes proxy) as Unknowns.DFDt, the first Navier-Stokes solve reports DIVERGED_FUNCTION_NANORINF after 0 iterations, so the residual itself is NaN. The swarm data holds no NaN at that point.

What works, same code, same environment:

  • test_0070 (Maxwell box, Stokes, quad mesh) passes.
  • The same box with UnstructuredSimplexBox (regular and irregular) reproduces the Stokes curve.
  • The same box with uw.systems.NavierStokes (SUPG momentum) and the swarm history set on Unknowns.DFDt runs without NaN.

What fails: the DFG cylinder script (~/+Simulations/navier_stokes_supg/scripts/dfg_cylinder.py, -uw_stress_transport particle), a gmsh mesh with the cylinder hole, inlet parabola ramped from rest, at Wi 1, resolution 5, unrefined, seven steps. NaN at the first solve with: fill_param 3 and 8; DEVSS on and off; cells proxy and nodes proxy; SUPG momentum and trace-back (SLCN) momentum. The swarm is advected before each solve with the previous velocity (zero at step 1), as in test_0070, with population_control = dict().

Not bisected further. The remaining differences from the passing box case are the gmsh mesh with a hole and its boundary labels, the ramped inflow, the outlet treatment, and the script's stress diagnostics. Reproducer: smoke_p_*.log under ~/+Simulations/stress_transport/cylinder/; the box probe is particle_simplex_probe.py (quad|simplex|simplex_regular, stokes|ns_supg).

Context: the other three stress histories run this benchmark to Wi 10 (#735, #737). The particle history is the one with no Courant floor and no per-step resampling, which is why it is wanted here.

Activity

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions