zh_wallband_diff Namespace Reference

Functions
	bed_sdf (N, npz)
	solve (N, kind, mu=0.1, F=1e-3, dt=80.0, warm_tol=1e-7, tail=40, max_steps=4000)

Variables
float	PHI0 = 0.125
	BED = os.environ.get("BED", "")
list	Ns = [int(x) for x in (sys.argv[1:] or [32, 64, 128])]
	prev = None
	fs
	ox
	sdf
	R
	fc
	_
float	sf = 0.5 * (sdf + np.roll(sdf, 1, axis=0))
	d = ox * (fc - fs)
	tot = float(d.mean())
float	band = 2.0
int	share = float(d[band].sum() / d.sum()) if abs(d.sum()) > 0 else float("nan")
	mx = float(np.abs(d[band]).max())
	rms = float(np.sqrt((d[band] ** 2).mean()))
dict	o = {}
	lr = np.log(N / prev[0])
	flush

Detailed Description

WHERE does the collocated-vs-staggered difference live, and does its amplitude grow?

The permeability gap does not vanish under refinement, and the constraint operator was exonerated
a-priori (net flux defect ~1e-5). If the surviving difference is localised in a wall band, the
arithmetic is forced: the band's VOLUME fraction shrinks as O(h), so for its contribution to the
volume-averaged velocity to stay constant the AMPLITUDE in the band must grow as O(1/h).

So: run both solvers on identical geometry, compare the alpha-weighted FACE fluxes (the conserved
quantity, and a like-for-like basis -- staggered get_u IS the face field, collocated get_uf is its
projected one), and split the difference by distance to the wall in CELL units.

  amplitude ~ 1/h  => mechanism found: a gauge/scaling error in the near-wall reconstruction
  amplitude ~ O(1) => the band contributes O(h) and the gap must come from somewhere else

    SDFLOW_BUILD=build_ge python tests/study/zh_wallband_diff.py [N ...]

Function Documentation

bed_sdf()

zh_wallband_diff.bed_sdf	(		N,
			npz
	)

Periodic union-of-spheres SDF from a packing, sampled on an N^3 grid (cubic box only).

Definition at line 31 of file zh_wallband_diff.py.

Referenced by solve().

solve()

zh_wallband_diff.solve	(		N,
			kind,
			mu = 0.1,
			F = 1e-3,
			dt = 80.0,
			warm_tol = 1e-7,
			tail = 40,
			max_steps = 4000
	)

Definition at line 56 of file zh_wallband_diff.py.

References bed_sdf(), and d.

Variable Documentation

PHI0

float zh_wallband_diff.PHI0 = 0.125

Definition at line 27 of file zh_wallband_diff.py.

BED

zh_wallband_diff.BED = os.environ.get("BED", "")

Definition at line 28 of file zh_wallband_diff.py.

Ns

list zh_wallband_diff.Ns = [int(x) for x in (sys.argv[1:] or [32, 64, 128])]

Definition at line 95 of file zh_wallband_diff.py.

prev

tuple zh_wallband_diff.prev = None

Definition at line 100 of file zh_wallband_diff.py.

fs

zh_wallband_diff.fs

Definition at line 102 of file zh_wallband_diff.py.

ox

zh_wallband_diff.ox

Definition at line 102 of file zh_wallband_diff.py.

sdf

zh_wallband_diff.sdf

Definition at line 102 of file zh_wallband_diff.py.

R

zh_wallband_diff.R

Definition at line 102 of file zh_wallband_diff.py.

fc

zh_wallband_diff.fc

Definition at line 103 of file zh_wallband_diff.py.

_

zh_wallband_diff._

protected

Definition at line 103 of file zh_wallband_diff.py.

sf

float zh_wallband_diff.sf = 0.5 * (sdf + np.roll(sdf, 1, axis=0))

Definition at line 105 of file zh_wallband_diff.py.

d

zh_wallband_diff.d = ox * (fc - fs)

Definition at line 106 of file zh_wallband_diff.py.

Referenced by solve().

tot

zh_wallband_diff.tot = float(d.mean())

Definition at line 107 of file zh_wallband_diff.py.

band

float zh_wallband_diff.band = 2.0

Definition at line 108 of file zh_wallband_diff.py.

share

int zh_wallband_diff.share = float(d[band].sum() / d.sum()) if abs(d.sum()) > 0 else float("nan")

Definition at line 109 of file zh_wallband_diff.py.

mx

zh_wallband_diff.mx = float(np.abs(d[band]).max())

Definition at line 110 of file zh_wallband_diff.py.

rms

zh_wallband_diff.rms = float(np.sqrt((d[band] ** 2).mean()))

Definition at line 111 of file zh_wallband_diff.py.

o

dict zh_wallband_diff.o = {}

Definition at line 112 of file zh_wallband_diff.py.

lr

zh_wallband_diff.lr = np.log(N / prev[0])

Definition at line 114 of file zh_wallband_diff.py.

flush

zh_wallband_diff.flush

Definition at line 121 of file zh_wallband_diff.py.