Vascular Bifurcations and Stenosis

Figure 8.1 — Vascular Bifurcations and Stenosis

The vascular bifurcation is the keystone of CFDrs’s biomedical flow support. It is generated as a CSG composition:

use cfd_schematics::bifurcation::BifurcationBuilder;
use leto::Point3;

let bif = BifurcationBuilder::new()
    .parent(Point3::new(0.0, 0.0, 0.0), 2.5)            // 5 mm diameter, mm units
    .child_a(Point3::new(0.0, 4.0, 0.0), 1.8, 0.35)    // 3.6 mm, 35° angle
    .child_b(Point3::new(0.0, 4.0, 0.0), 1.8, -0.35)   // mirror child
    .stenosed_a(0.55)                                   // 55% area stenosis
    .build();

Boundary conditions follow the Murray-style split, with Reynolds-scaled flow division between children A and B. CFDrs composes this CSG with the 1-D reduced solver to compute pressure and shear stress along each parent / child branch.

Rheology Choices

use cfd_1d::blood_rheology::Rheology;

let rheo = Rheology::carreau {          // μ_0, μ_∞, λ, n
    mu_inf: 0.00345,
    mu_0:   0.056,
    lambda: 3.313,
    n:      0.3568,
};

Carreau, Carreau-Yasuda, Casson, and Power-law models are all supported. The rheology is a trait the solver consumes per timestep — switching models is a single field change.

Examples Referenced by This Chapter

• bifurcation_2d_blood_validation — 2-D Frauhofer-Keller bifurcation with non-Newtonian blood.
• venturi_blood_flow_validation — venturi stenosis under Newtonian and Carreau rheology.
• cross_fidelity_branching — concurrently run a 1-D, 2-D, and 3-D branch of a vascular bifurcation and compare outputs.

Further Reading

• For microfluidic mixing screens, FDA shear limits, and TPMS scaffolds, see Non-Newtonian Fluids and Blood Rheology.
• cfd-schematics source