Parametric Y-Bifurcation

Parent + two daughters — AortaCFD-X

Parent vessel

D parent

20.0

L parent

Curvature

deg

0 = straight parent

Bifurcation

Total angle

deg

Full angle between the two daughters

Asymmetry

0.00

0 = symmetric, ±1 = all one side

Junction smoothing

5.0

Visual blob radius (not CFD-grade)

Murray's law

$d_p^3 = d_1^3 + d_2^3$ — when on, daughter diameters are derived

Split ratio

0.50

Flow fraction to daughter 1 (0.5 = equal)

Daughter 1

D 1

15.9

Disabled — Murray's law is on

L 1

Daughter 2

D 2

15.9

Disabled — Murray's law is on

L 2

Display

Solid Wireframe Both

Centrelines Junction marker

Smooth preview (SDF)

Marching cubes on capsule SDF with polynomial smooth-min — matches generate_bifurcation_smooth()

MC resolution

vox

Voxels along the longest axis. 80 is a good balance; ≥120 looks crisper at ~2× the rebuild time.

Wall

Centreline

Junction J

Murray's law: $d_p^3 = d_1^3 + d_2^3$

Optimal area: $A_1 + A_2 \approx 1.26\,A_p$ (equal daughters)

The exported STL is a multi-solid ASCII file with named patches — wall, inlet, outlet_1, outlet_2 — readable directly by snappyHexMesh. In smooth preview mode the surface is fully watertight; in fast preview mode the three constituent tubes overlap slightly near the junction (snappyHexMesh handles the union when building the volume mesh). For maximum mesh quality and a guaranteed boolean union, use the Python primitive generate_bifurcation_union().