Functions
	make (variable_mu, solver=None, dt=2.0)

	raises (fn)

	main ()

Variables
int	N = 16

Detailed Description

The momentum solver never silently drops a variable viscosity.

The velocity multigrid takes a SCALAR mu. Combined with a variable viscosity (a 'mu' closure or
set_property_mode('variable')) it used to solve with the constant set_mu value instead: on a
mirror-pair case the explicit multigrid with mu(T) differed from its own constant-mu run by only
2e-4 and from the red-black smoother by 50-70 %. Now:

  1. an EXPLICIT set_velocity_solver('multigrid') / set_velocity_multigrid(True) raises ValueError
     with a variable viscosity, in either order (solver first, then the closure / the mode; or
     the other way round), and names the cause;
  2. the AUTO rule (which picks the V-cycle once kappa = 1 + 4 dt mu sum(w) / rho >= 13) keeps a
     variable viscosity on the red-black smoother -- velocity_multigrid_active() is False after
     the first step, while the same case at constant mu takes the V-cycle -- and the variable-mu
     result equals the explicit 'gauss_seidel' run bitwise.

Run: OMP_NUM_THREADS=4 PYTHONPATH=<build> python tests/python/test_velocity_solver_variable_mu.py
Exit 0 pass, 1 fail, 77 skipped (no module).

Function Documentation

◆ make()

test_velocity_solver_variable_mu.make	(	variable_mu,
		solver = `None`,
		dt = `2.0`
	)

Walled box, a transported scalar T driving the body force (and mu(T) when variable_mu).
dt = 2, mu = 0.5: kappa = 1 + 12 * 1.0 = 13 -> AUTO picks the V-cycle at constant mu.

Definition at line 33 of file test_velocity_solver_variable_mu.py.

Referenced by main().