Postprocessing

Embedded-boundary diagnostics are available for StokesModelMono states/solutions.

1. embedded_boundary_quantities

embedded_boundary_quantities(model, x; mu=model.mu, pressure_reconstruction=:linear, x0=nothing)

Returns named tuple fields:

• stress: stress tensor at pressure-grid interface cells,
• traction: traction vector at interface cells,
• force_density: traction * Gamma per interface cell,
• interface_indices: active interface cell indices,
• force: integrated total force,
• force_pressure: integrated pressure contribution,
• force_viscous: integrated viscous contribution,
• torque: 2D scalar or 3D vector about x0.

pressure_reconstruction options:

• :none: use cell pressure value,
• :linear: linear trace reconstruction with pressure gradient.

2. Convenience Wrappers

• embedded_boundary_traction(model, x; kwargs...)
• embedded_boundary_stress(model, x; kwargs...)
• integrated_embedded_force(model, x; kwargs...)

Each also accepts sys::LinearSystem and uses sys.x.

3. Sign/Interpretation Notes

• Traction is computed as sigma * n with interface normal from capacity data.
• force is the integrated traction force on the embedded boundary.
• Split outputs satisfy force ≈ force_pressure + force_viscous.
• Torque is evaluated about x0 (defaults to origin).

4. Usage Snippet

sys = solve_steady!(model)
q = embedded_boundary_quantities(model, sys; pressure_reconstruction=:linear, x0=(0.5, 0.5))
println("F_total = ", q.force)
println("F_pressure = ", q.force_pressure)
println("F_viscous = ", q.force_viscous)
println("Torque = ", q.torque)

5. Current Scope

Implemented for StokesModelMono only in current API.