test_chamber_geometry_volume Namespace Reference

Functions
	_tangency_radius (R_t, theta)
	_drawn_volume (L_cyl, L_con, R_c, R_t, theta, n=200001)
	test_drawn_volume_matches_commanded_lstar (D_c, Lstar, theta)
	test_old_exponent_would_fail ()
float	_real_drawn_lstar (float D_c, float Lstar, float theta)
	test_generated_contour_has_the_commanded_lstar (Lstar, theta_deg)
	test_entrance_arc_volume_is_not_negligible ()
	test_tangency_radius_is_above_the_throat ()

Variables
	_PC
	_F
	_D_EXIT

Detailed Description

The drawn chamber must actually hold the commanded L* x A_t.

Guards the convergent-volume term in chamber_length_calc. The old form used
(eps^(1/3) - 1) instead of (eps^(3/2) - 1), understating the cone by ~18x at
typical contraction ratios and padding the barrel to compensate.

Function Documentation

_drawn_volume()

test_chamber_geometry_volume._drawn_volume ( L_cyl, L_con, R_c, R_t, theta, n = 200001 )

protected

Volume of the solid of revolution ACTUALLY generated: cylinder, cone to the arc
tangency radius, then the 1.5*R_t entrance arc down to the throat.

This used to draw a straight cone all the way to R_t, which is not what the generator
makes -- so it reproduced the very convention the volume arithmetic got wrong and could
not catch the entrance-arc bug. See the real-contour tests at the bottom of this file.

Definition at line 23 of file test_chamber_geometry_volume.py.

References _tangency_radius().

Referenced by test_drawn_volume_matches_commanded_lstar(), and test_old_exponent_would_fail().

_real_drawn_lstar()

float test_chamber_geometry_volume._real_drawn_lstar ( float D_c, float Lstar, float theta )

protected

L* of the contour chamber_geometry_calc ACTUALLY generates, face to throat.

Definition at line 107 of file test_chamber_geometry_volume.py.

Referenced by test_generated_contour_has_the_commanded_lstar().

_tangency_radius()

test_chamber_geometry_volume._tangency_radius ( R_t, theta )

protected

Radius where the 1.5*R_t entrance arc is tangent to a cone of half-angle theta.

Definition at line 18 of file test_chamber_geometry_volume.py.

Referenced by _drawn_volume(), test_drawn_volume_matches_commanded_lstar(), and test_old_exponent_would_fail().

test_drawn_volume_matches_commanded_lstar()

test_chamber_geometry_volume.test_drawn_volume_matches_commanded_lstar	(		D_c,
			Lstar,
			theta )

Definition at line 51 of file test_chamber_geometry_volume.py.

References _drawn_volume(), and _tangency_radius().

test_entrance_arc_volume_is_not_negligible()

test_chamber_geometry_volume.test_entrance_arc_volume_is_not_negligible

(

)

Guard the guard: if the arc term were dropped the test above must fail, not pass.

Definition at line 133 of file test_chamber_geometry_volume.py.

test_generated_contour_has_the_commanded_lstar()

test_chamber_geometry_volume.test_generated_contour_has_the_commanded_lstar	(		Lstar,
			theta_deg )

The chamber that gets DRAWN must hold the volume that was asked for.

Definition at line 122 of file test_chamber_geometry_volume.py.

References _real_drawn_lstar().

test_old_exponent_would_fail()

test_chamber_geometry_volume.test_old_exponent_would_fail

(

)

The pre-fix formula overshoots by ~10 % -- proves this test has teeth.

Definition at line 68 of file test_chamber_geometry_volume.py.

References _drawn_volume(), and _tangency_radius().

test_tangency_radius_is_above_the_throat()

test_chamber_geometry_volume.test_tangency_radius_is_above_the_throat

(

)

r_tan = R_t(1 + 1.5(1-cos theta)) must exceed R_t, or the cone would run past the arc.

Definition at line 146 of file test_chamber_geometry_volume.py.

Variable Documentation

_D_EXIT

test_chamber_geometry_volume._D_EXIT

protected

Definition at line 104 of file test_chamber_geometry_volume.py.

_F

test_chamber_geometry_volume._F

protected

Definition at line 104 of file test_chamber_geometry_volume.py.

_PC

test_chamber_geometry_volume._PC

protected

Definition at line 104 of file test_chamber_geometry_volume.py.