Chapter 6 — Geometry Construction and CFD Coupling

Figure 12.1 — Constructive Solid Geometry for CFD

CFDrs separates solid-mesh operations from design-time microfluidic topology. The two representations have different contracts and do not share a synthetic cross-domain facade.

Canonical Owners

Solid Meshes and CSG

The root CSG examples construct cfd-mesh primitives through PrimitiveMesh::build. They validate signed volume, watertightness, connected components, Euler characteristic, and normal orientation. Boolean composition uses one operation enum:

use cfd_mesh::application::csg::boolean::{csg_boolean, BooleanOp};

let union = csg_boolean(BooleanOp::Union, &left, &right)?;
let intersection = csg_boolean(BooleanOp::Intersection, &left, &right)?;
let difference = csg_boolean(BooleanOp::Difference, &left, &right)?;

These operations return IndexedMesh values. The examples optionally write STL output after validating each result.

Design-Time Network Blueprints

cfd-schematics owns planar channel topology, layout, and visualization. Its preset factories—including venturi_rect, serpentine_rect, symmetric_bifurcation, and symmetric_trifurcation—produce validated NetworkBlueprint values. A blueprint carries nodes, channels, cross-section specifications, topology metadata, and rendering hints. It is a design-time network description, not a volume mesh or a 2-D PDE grid.

The cfd-1d solver consumes blueprint node and channel specifications for lumped resistance-network models. Continuous cfd-2d and cfd-3d solvers retain their own grid and mesh construction boundaries.

Boundary Handoff

Physical conditions use cfd_core::physics::boundary::BoundaryCondition<T>. Named regions are stored in BoundaryConditionSet<T>; solver-specific setup code associates those names with grid faces or mesh regions. Schematic branch metadata describes topology and does not replace the physical boundary-condition contract.

Examples Referenced by This Chapter

• csg_primitives_demo validates primitive tessellation and topology.
• csg_operations validates union, intersection, and difference results.
• csg_cfd_simulation demonstrates the existing CSG-to-solver example path.
• mesh_3d_integration exercises a three-dimensional mesh integration path.
• dimension_scenarios_plots compares the repository’s fidelity-specific examples.
• The additional Part VI pages document the shipped schematic generator and preset examples with their exact Cargo target names.

Further Reading

• cfd-schematics source
• cfd-core boundary source
• Biomedical and Specialized Flows
• Turbulence, Multiphase, and Cavitation