duct_re_gate Namespace Reference

Functions
	abraham_cd (re)
	run (duct)

Variables
int	DH = float(sys.argv[1]) if len(sys.argv) > 1 else 8.0
int	RE = float(sys.argv[2]) if len(sys.argv) > 2 else 1.5
int	STEPS = int(sys.argv[3]) if len(sys.argv) > 3 else 800
float	U = 0.02
float	NU = U * DH / RE
float	DT = 3.2 if RE > 0.5 else 8.0
	KI_I
	KI_R
float	OFF = 0.3
float	WALL = 4.3
	L = int(np.ceil((100 / 15 * DH + 2 * WALL) / 8) * 8)
tuple	WX = (L - 100 / 15 * DH) / 2
	NY = int(np.ceil(12 * DH / 8) * 8)
	fP
	FP
	vP
	_
	fD
	FD
	vD
	u = vm[-1][1]
int	re = u * DH / NU
	cd = f / (0.5 * u ** 2 * np.pi * (DH / 2) ** 2)
	K = fD / fP * (vP[-1][1] / vD[-1][1])

Detailed Description

Confinement at finite Re, static twin of the ten Cate tank.

Lab frame: tank at rest, fluid at rest, sphere falls at -U. Sphere frame: sphere FIXED, duct walls
translate at +U, far fluid moves at +U -- plug flow, zero wall shear, exactly the quiescent lab
state. No moving geometry (the duct is y-invariant, so its translation is a pure wall-velocity
datum), so the finite-Re Galilean gate's clean bill applies and what is measured here is the
solver's confinement physics alone.

K(Re) = Cd_duct(Re) / Cd_periodic(Re) is the confinement factor. Creeping expectation for a sphere
on the axis of a square duct with d/W = 0.15 (Faxen): K ~ 1.39. At Re = 1.5 with the wall at
3.3 d >> nu/U = 0.67 d the Stokeslet is screened and the experiment implies K ~ 1.05-1.15. A solver
that returns ~1.39 at Re = 1.5 is not screening.

Usage: PYTHONPATH=<flow build> python duct_re_gate.py [DH=8] [Re=1.5] [STEPS=800]

Function Documentation

abraham_cd()

duct_re_gate.abraham_cd

(

re

)

Definition at line 35 of file duct_re_gate.py.

Referenced by run().

run()

duct_re_gate.run

(

duct

)

Definition at line 39 of file duct_re_gate.py.

References abraham_cd(), and mean().

Variable Documentation

DH

int duct_re_gate.DH = float(sys.argv[1]) if len(sys.argv) > 1 else 8.0

Definition at line 21 of file duct_re_gate.py.

RE

int duct_re_gate.RE = float(sys.argv[2]) if len(sys.argv) > 2 else 1.5

Definition at line 22 of file duct_re_gate.py.

STEPS

int duct_re_gate.STEPS = int(sys.argv[3]) if len(sys.argv) > 3 else 800

Definition at line 23 of file duct_re_gate.py.

U

float duct_re_gate.U = 0.02

Definition at line 24 of file duct_re_gate.py.

NU

float duct_re_gate.NU = U * DH / RE

Definition at line 25 of file duct_re_gate.py.

DT

float duct_re_gate.DT = 3.2 if RE > 0.5 else 8.0

Definition at line 26 of file duct_re_gate.py.

KI_I

duct_re_gate.KI_I

Definition at line 27 of file duct_re_gate.py.

KI_R

duct_re_gate.KI_R

Definition at line 27 of file duct_re_gate.py.

OFF

float duct_re_gate.OFF = 0.3

Definition at line 28 of file duct_re_gate.py.

WALL

float duct_re_gate.WALL = 4.3

Definition at line 29 of file duct_re_gate.py.

L

duct_re_gate.L = int(np.ceil((100 / 15 * DH + 2 * WALL) / 8) * 8)

Definition at line 30 of file duct_re_gate.py.

WX

tuple duct_re_gate.WX = (L - 100 / 15 * DH) / 2

Definition at line 31 of file duct_re_gate.py.

NY

duct_re_gate.NY = int(np.ceil(12 * DH / 8) * 8)

Definition at line 32 of file duct_re_gate.py.

fP

duct_re_gate.fP

Definition at line 88 of file duct_re_gate.py.

FP

duct_re_gate.FP

Definition at line 88 of file duct_re_gate.py.

vP

duct_re_gate.vP

Definition at line 88 of file duct_re_gate.py.

_

duct_re_gate._

protected

Definition at line 88 of file duct_re_gate.py.

fD

duct_re_gate.fD

Definition at line 89 of file duct_re_gate.py.

FD

duct_re_gate.FD

Definition at line 89 of file duct_re_gate.py.

vD

duct_re_gate.vD

Definition at line 89 of file duct_re_gate.py.

u

duct_re_gate.u = vm[-1][1]

Definition at line 91 of file duct_re_gate.py.

re

int duct_re_gate.re = u * DH / NU

Definition at line 92 of file duct_re_gate.py.

cd

duct_re_gate.cd = f / (0.5 * u ** 2 * np.pi * (DH / 2) ** 2)

Definition at line 93 of file duct_re_gate.py.

K

duct_re_gate.K = fD / fP * (vP[-1][1] / vD[-1][1])

Definition at line 98 of file duct_re_gate.py.