Functions
	arg (name, default, cast=float)

	tbf_read (path, shape)

	interp_component (src, src_pos, dst_pos)

	load_tbf_ic ()

	laminar_ic ()

	sphere_frac (shape, R, c, sub=16)

	new_acc ()

	sample (acc, s, t)

	profiles (acc)

	save_ckpt (path, s, step, t, acc, blocks, alpha0)

	load_ckpt (path)

	block_state (s)

	main ()

Variables
	TBF = str(arg("--tbf", "/home/frankp/Codes/TBFsolver/channel_18/0", str))

	NY = int(arg("--ny", 80, int))

	NSTEP = int(arg("--steps", 20000, int))

	CKPT = str(arg("--ckpt", "channel_18_ckpt.npz", str))

	OUT = str(arg("--out", "channel_18_stats.npz", str))

	LOGJ = str(arg("--chunklog", "channel_18_chunks.jsonl", str))

	WALL = float(arg("--wall", 1e18))

	TARGET = float(arg("--turnovers", 20.0))

	STATS_START = float(arg("--stats-start", 4.0))

	SAMPLE = int(arg("--sample", 10, int))

	CKEVERY = int(arg("--ckpt-every", 2000, int))

	DTEVERY = int(arg("--dt-every", 1, int))

	DTSAFE = float(arg("--dt-safety", 0.25))

	PRINTEVERY = int(arg("--print-every", 200, int))

str	QUICK = "--quick" in sys.argv

	LX

	LY

	LZ

	RHO_L

	RHO_G

float	MU = 3.33333333333333e-4

float	SIGMA = 5.0e-3

float	GCH = 0.1

float	RET = 127.3

float	RE = 1.0 / MU

tuple	TAUW = (RET / RE) ** 2

float	UTAU = RET * MU

float	RBUB = 0.125

	NBX

	NBY

	NBZ

	S = NY / LY

int	NX = int(round(LX * S / 16)) * 16

int	NZ = int(round(LZ * S / 16)) * 16

	LXC

	LZC

tuple	KEYS

Detailed Description

VoF Part III rung W3 (WO-W3) — TBFsolver's `channel_18` to a statistically steady state.

WO-W12 gate 4 transcribed the case and ran it for 0.84 eddy turnovers on one shared workstation
GPU (`tests/study/vof_channel_18.py`).  W3 is the same case run to ~20 eddy turnovers on Snellius
H100s, which no single job's wall clock can hold, so this driver differs from that one in exactly
three ways and in nothing else:

  1. **it checkpoints and restarts** — velocity + every marker's OWN colour (`vof_block_color` /
     `enable_vof_blocks_from_colors`, added for this rung: re-seeding from the union field is
     NOT exact once two markers touch, WO-W12 open item 5),
  2. **it accumulates the statistics across chunks** (running sums live in the checkpoint), with an
     explicit transient window that is discarded, and
  3. **it stops on a wall-clock budget** as well as on a step/turnover target, so a chunk always
     ends with a checkpoint on disk.

The physical case is WO-W12's transcription verbatim — see `tests/study/vof_channel_18.py` for the
derivation of every number from the Fortran that consumes `channel_18/specs`:

    geometry   Lx = pi (streamwise, periodic), Ly = 2 (wall-normal, WALLS), Lz = pi/2 (spanwise,
               periodic), h = 1;  mapped onto an ISOTROPIC ny=80 grid -> 128 x 80 x 64.
    fluids     rho_l = 1, rho_g = 0.1;  mu_l = mu_g = 3.3333e-4;  sigma = 5e-3.
    driving    x-momentum source  tau_w + (rho - <rho>) gCH,  tau_w = (Re_tau/Re)^2 = 1.800588e-3,
               gCH = 0.1 a STREAMWISE GRAVITY (buoyancy only) -> u_tau = 0.0424333 by construction.
               The bubbles are driven against the mean flow: a DOWNFLOW channel.
    bubbles    18 spheres of R = 0.125 h on the centreline, 6 x 3 in (x, z); void fraction 1.49 %.
    IC         `channel_18/0/{ux,uy,uz}`, TBFsolver's own converged single-phase snapshot,
               trilinearly resampled onto our grid (U_b = 0.6113).

One eddy turnover is h/u_tau; the driver reports `t u_tau / h` everywhere.

STATISTICS (plane averages over x and z, per wall-normal row; sampled every `--sample` steps and
accumulated only after `t u_tau/h >= --stats-start`):

    <C>(y)                     the void fraction (C is the GAS indicator in this transcription:
                               rho = rho_l + (rho_g - rho_l) C)
    <u>(y), <v>(y), <w>(y)     cell-centred velocity means
    <u'u'>, <v'v'>, <w'w'>     rms components (from the accumulated squares)
    <u'v'>                     the Reynolds shear stress
    the same six conditioned on the LIQUID with the weight (1 - C)  ->  <u>_l etc.

    u_tau is reported three ways: the imposed 0.0424333, the wall gradient of <u>_l at the first
    cell, and the wall gradient at both walls separately (their spread is the convergence measure).

Usage (one chunk):
  PYTHONPATH=<build> python run_channel_18.py --ckpt ck.npz --steps 20000 --wall 39000 \
      --turnovers 20 --stats-start 4 --out results.npz
Re-running the same command resumes from `ck.npz` and stops when the turnover target is reached.

Function Documentation

◆ arg()

run_channel_18.arg	(	name,
		default,
		cast = `float`
	)

Definition at line 61 of file run_channel_18.py.

◆ tbf_read()

run_channel_18.tbf_read	(	path,
		shape
	)

Definition at line 112 of file run_channel_18.py.

Referenced by load_tbf_ic().

◆ interp_component()

run_channel_18.interp_component	(	src,
		src_pos,
		dst_pos
	)

Definition at line 121 of file run_channel_18.py.

References slice().

Referenced by load_tbf_ic().

◆ load_tbf_ic()

run_channel_18.load_tbf_ic ( )

Definition at line 144 of file run_channel_18.py.

References interp_component(), and tbf_read().

Referenced by main().

◆ laminar_ic()

run_channel_18.laminar_ic ( )

Definition at line 167 of file run_channel_18.py.

Referenced by main().

◆ sphere_frac()

run_channel_18.sphere_frac	(	shape,
		R,
		c,
		sub = `16`
	)

Definition at line 181 of file run_channel_18.py.

References mean().

Referenced by main().

◆ new_acc()

run_channel_18.new_acc ( )

Definition at line 200 of file run_channel_18.py.

Referenced by load_ckpt(), and main().

◆ sample()

run_channel_18.sample	(	acc,
		s,
		t
	)

One plane-averaged sample. Velocities are interpolated to CELL CENTRES first.

flow's `u` is the LOW-x face of each cell and x is periodic, `v` the low-y face (the +y face of
the last row is the wall, v = 0), `w` the low-z face with z periodic — so the centred value is
the mean of the cell's two faces on each axis.

Definition at line 208 of file run_channel_18.py.

References mean().

Referenced by main().

◆ profiles()

run_channel_18.profiles ( acc )

Turn the running sums into the reported profiles (dimensional, then in wall units).

Definition at line 251 of file run_channel_18.py.

Referenced by main().

◆ save_ckpt()

run_channel_18.save_ckpt	(	path,
		s,
		step,
		t,
		acc,
		blocks,
		alpha0
	)

Definition at line 292 of file run_channel_18.py.

Referenced by main().

◆ load_ckpt()

run_channel_18.load_ckpt ( path )

Definition at line 316 of file run_channel_18.py.

References new_acc().

Referenced by main().

◆ block_state()

run_channel_18.block_state ( s )

{box, own colour} per marker — the complete state of the block container.

Definition at line 335 of file run_channel_18.py.

Referenced by main().

◆ main()

run_channel_18.main ( )

Definition at line 346 of file run_channel_18.py.

References block_state(), laminar_ic(), load_ckpt(), load_tbf_ic(), main(), new_acc(), profiles(), sample(), save_ckpt(), and sphere_frac().

Referenced by main().

Variable Documentation

◆ TBF

run_channel_18.TBF = str(arg("--tbf", "/home/frankp/Codes/TBFsolver/channel_18/0", str))

Definition at line 67 of file run_channel_18.py.

◆ NY

run_channel_18.NY = int(arg("--ny", 80, int))

Definition at line 68 of file run_channel_18.py.

◆ NSTEP

run_channel_18.NSTEP = int(arg("--steps", 20000, int))

Definition at line 69 of file run_channel_18.py.

◆ CKPT

run_channel_18.CKPT = str(arg("--ckpt", "channel_18_ckpt.npz", str))

Definition at line 70 of file run_channel_18.py.

◆ OUT

run_channel_18.OUT = str(arg("--out", "channel_18_stats.npz", str))

Definition at line 71 of file run_channel_18.py.

◆ LOGJ

run_channel_18.LOGJ = str(arg("--chunklog", "channel_18_chunks.jsonl", str))

Definition at line 72 of file run_channel_18.py.

◆ WALL

run_channel_18.WALL = float(arg("--wall", 1e18))

Definition at line 73 of file run_channel_18.py.

◆ TARGET

run_channel_18.TARGET = float(arg("--turnovers", 20.0))

Definition at line 74 of file run_channel_18.py.

◆ STATS_START

run_channel_18.STATS_START = float(arg("--stats-start", 4.0))

Definition at line 75 of file run_channel_18.py.

◆ SAMPLE

run_channel_18.SAMPLE = int(arg("--sample", 10, int))

Definition at line 76 of file run_channel_18.py.

◆ CKEVERY

run_channel_18.CKEVERY = int(arg("--ckpt-every", 2000, int))

Definition at line 77 of file run_channel_18.py.

◆ DTEVERY

run_channel_18.DTEVERY = int(arg("--dt-every", 1, int))

Definition at line 78 of file run_channel_18.py.

◆ DTSAFE

run_channel_18.DTSAFE = float(arg("--dt-safety", 0.25))

Definition at line 79 of file run_channel_18.py.

◆ PRINTEVERY

run_channel_18.PRINTEVERY = int(arg("--print-every", 200, int))

Definition at line 80 of file run_channel_18.py.

◆ QUICK

str run_channel_18.QUICK = "--quick" in sys.argv

Definition at line 81 of file run_channel_18.py.

◆ LX

run_channel_18.LX

Definition at line 92 of file run_channel_18.py.

◆ LY

run_channel_18.LY

Definition at line 92 of file run_channel_18.py.

◆ LZ

run_channel_18.LZ

Definition at line 92 of file run_channel_18.py.

◆ RHO_L

run_channel_18.RHO_L

Definition at line 93 of file run_channel_18.py.

◆ RHO_G

run_channel_18.RHO_G

Definition at line 93 of file run_channel_18.py.

◆ MU

float run_channel_18.MU = 3.33333333333333e-4

Definition at line 94 of file run_channel_18.py.

◆ SIGMA

float run_channel_18.SIGMA = 5.0e-3

Definition at line 95 of file run_channel_18.py.

◆ GCH

float run_channel_18.GCH = 0.1

Definition at line 96 of file run_channel_18.py.

◆ RET

float run_channel_18.RET = 127.3

Definition at line 97 of file run_channel_18.py.

◆ RE

float run_channel_18.RE = 1.0 / MU

Definition at line 98 of file run_channel_18.py.

◆ TAUW

tuple run_channel_18.TAUW = (RET / RE) ** 2

Definition at line 99 of file run_channel_18.py.

◆ UTAU

float run_channel_18.UTAU = RET * MU

Definition at line 100 of file run_channel_18.py.

◆ RBUB

float run_channel_18.RBUB = 0.125

Definition at line 101 of file run_channel_18.py.

◆ NBX

run_channel_18.NBX

Definition at line 102 of file run_channel_18.py.

◆ NBY

run_channel_18.NBY

Definition at line 102 of file run_channel_18.py.

◆ NBZ

run_channel_18.NBZ

Definition at line 102 of file run_channel_18.py.

◆ S

run_channel_18.S = NY / LY

Definition at line 105 of file run_channel_18.py.

◆ NX

int run_channel_18.NX = int(round(LX * S / 16)) * 16

Definition at line 106 of file run_channel_18.py.

◆ NZ

int run_channel_18.NZ = int(round(LZ * S / 16)) * 16

Definition at line 107 of file run_channel_18.py.

◆ LXC

run_channel_18.LXC

Definition at line 108 of file run_channel_18.py.

◆ LZC

run_channel_18.LZC

Definition at line 108 of file run_channel_18.py.

◆ KEYS

tuple run_channel_18.KEYS

Initial value:

1= ("C", "u", "v", "w", "uu", "vv", "ww", "uv",

2 "L", "Lu", "Lv", "Lw", "Luu", "Lvv", "Lww", "Luv")

Definition at line 196 of file run_channel_18.py.

Functions

Variables

Detailed Description

Function Documentation

◆ arg()

◆ tbf_read()

◆ interp_component()

◆ load_tbf_ic()

◆ laminar_ic()

◆ sphere_frac()

◆ new_acc()

◆ sample()

◆ profiles()

◆ save_ckpt()

◆ load_ckpt()

◆ block_state()

◆ main()

Variable Documentation

◆ TBF

◆ NY

◆ NSTEP

◆ CKPT

◆ OUT

◆ LOGJ

◆ WALL

◆ TARGET

◆ STATS_START

◆ SAMPLE

◆ CKEVERY

◆ DTEVERY

◆ DTSAFE

◆ PRINTEVERY

◆ QUICK

◆ LX

◆ LY

◆ LZ

◆ RHO_L

◆ RHO_G

◆ MU

◆ SIGMA

◆ GCH

◆ RET

◆ RE

◆ TAUW

◆ UTAU

◆ RBUB

◆ NBX

◆ NBY

◆ NBZ

◆ S

◆ NX

◆ NZ

◆ LXC

◆ LZC

◆ KEYS