rotation_gate Namespace Reference

Functions
	make (N, R, dt, om, advect=False)
	static_lambda (N, R, steps=1000, dt=20.0)
	part_a ()
	part_b (lam)

Variables
	RHO
	MU
int	OM0 = 1e-3
	KN_R
	KI_I
	KI_R
	ok_a
	lam
bool	ok_b = True

Detailed Description

ROTATION GATE: the reaction TORQUE against the exact Stokes torque 8*pi*mu*a^3*Omega.

Part A (statics): a sphere spinning in place. The geometry never moves (a sphere is invariant
under its own rotation), so this isolates the torque evaluation completely. Before the v3
transposed-stress wall term the reaction torque was a STRUCTURAL -31% (the budget measures the
Laplacian-form wall flux; the physical traction adds mu*(grad u)^T.n = mu*(n x Omega), whose force
integral is zero -- which is why the force never saw it -- and whose torque integral is exactly one
third). With it, the error is the aperture first-moment discretisation and CONVERGES.

Part B (dynamics): the full ResolvedCfdDem hand-off. The same sphere, given physical inertia
I = (2/5) m R^2 and an initial spin, decays by the torque the flow hands to dem
(apply_torque=True). Reference: the decay rate 1/tau = 8*pi*mu*R^3*lambda_rot / I with lambda_rot
the SAME BOX's own rotational drag measured in part A -- the settling-gate calibration pattern, so
the discretisation bias cancels between calibration and prediction.

Needs flow (+ dem + coupling for part B) on PYTHONPATH.

Function Documentation

make()

rotation_gate.make	(		N,
			R,
			dt,
			om,
			advect = False
	)

Definition at line 28 of file rotation_gate.py.

Referenced by static_lambda().

static_lambda()

rotation_gate.static_lambda	(		N,
			R,
			steps = 1000,
			dt = 20.0
	)

Definition at line 49 of file rotation_gate.py.

References make().

Referenced by part_a().

part_a()

rotation_gate.part_a

(

)

Definition at line 58 of file rotation_gate.py.

References static_lambda().

part_b()

rotation_gate.part_b

(

lam

)

Definition at line 81 of file rotation_gate.py.

Variable Documentation

RHO

rotation_gate.RHO

Definition at line 23 of file rotation_gate.py.

MU

rotation_gate.MU

Definition at line 23 of file rotation_gate.py.

OM0

int rotation_gate.OM0 = 1e-3

Definition at line 24 of file rotation_gate.py.

KN_R

rotation_gate.KN_R

Definition at line 25 of file rotation_gate.py.

KI_I

rotation_gate.KI_I

Definition at line 25 of file rotation_gate.py.

KI_R

rotation_gate.KI_R

Definition at line 25 of file rotation_gate.py.

ok_a

rotation_gate.ok_a

Definition at line 136 of file rotation_gate.py.

lam

rotation_gate.lam

Definition at line 136 of file rotation_gate.py.

ok_b

rotation_gate.ok_b = True

Definition at line 137 of file rotation_gate.py.