# API & Types

Types

• AdvDiffModelMono{N,T,...}
• AdvDiffModelDiph{N,T,...}
• MovingAdvDiffModelMono{N,T,...}
• MovingAdvDiffModelDiph{N,T,...}
• AdvDiffCoupledModelMono
  • Wrapper/adaptor for PenguinSolverCore block coupling.
  • Exposes :concentration and accepts incoming :velocity.
  • Uses advance_steady! / advance_unsteady! hooks through SolverCore.

Constructors (fixed geometry)

• AdvDiffModelMono(cap, D, uω, uγ; source=..., bc=..., bc_interface_diff=..., layout=..., coeff_mode=:harmonic, scheme=Centered())
• AdvDiffModelDiph(cap1, D1, u1ω, u1γ, cap2, D2, u2ω, u2γ; source=..., bc=..., ic=..., bc_interface=..., layout=..., coeff_mode=:harmonic, scheme=Centered())
• AdvDiffModelDiph(cap, D1, D2, u1ω, u1γ, u2ω, u2γ; ...) (shared-capacity shorthand)

Constructors (moving geometry)

• MovingAdvDiffModelMono(grid, body, D, uω, uγ; wγ=..., source=..., bc=..., bc_interface_diff=..., layout=..., coeff_mode=:harmonic, scheme=Centered(), geom_method=:vofijul)
• MovingAdvDiffModelDiph(grid, body1, D1, u1ω, u1γ, D2, u2ω, u2γ; wγ=..., source=..., body2=..., bc=..., ic=..., bc_interface=..., layout=..., coeff_mode=:harmonic, scheme=Centered(), geom_method=:vofijul)
• Composition overloads from pre-built moving diffusion models are also available.

Public functions

• assemble_steady_mono!(sys::LinearSystem, model::AdvDiffModelMono, t)
• assemble_steady_diph!(sys::LinearSystem, model::AdvDiffModelDiph, t)
• assemble_unsteady_mono!(sys::LinearSystem, model::AdvDiffModelMono, uⁿ, t, dt, scheme_or_theta)
• assemble_unsteady_diph!(sys::LinearSystem, model::AdvDiffModelDiph, uⁿ, t, dt, scheme_or_theta)
• assemble_unsteady_mono_moving!(sys::LinearSystem, model::MovingAdvDiffModelMono, uⁿ, t, dt, scheme_or_theta)
• assemble_unsteady_diph_moving!(sys::LinearSystem, model::MovingAdvDiffModelDiph, uⁿ, t, dt, scheme_or_theta)
• solve_steady!(model::AdvDiffModelMono; t=zero(T), method=:direct, kwargs...)
• solve_steady!(model::AdvDiffModelDiph; t=zero(T), method=:direct, kwargs...)
• solve_unsteady!(model::AdvDiffModelMono, u0, tspan; dt, scheme=:BE|:CN|θ, method=:direct, save_history=true, kwargs...)
• solve_unsteady!(model::AdvDiffModelDiph, u0, tspan; dt, scheme=:BE|:CN|θ, method=:direct, save_history=true, kwargs...)
• solve_unsteady_moving!(model::MovingAdvDiffModelMono, u0, tspan; dt, scheme=:BE|:CN|θ, method=:direct, save_history=true, kwargs...)
• solve_unsteady_moving!(model::MovingAdvDiffModelDiph, u0, tspan; dt, scheme=:BE|:CN|θ, method=:direct, save_history=true, kwargs...)
• rebuild!(model::AdvDiffModelMono, moments; bc=zero(T), t=zero(T))
• rebuild!(model::AdvDiffModelDiph, moments; bc=zero(T), t=zero(T))
• update_advection_ops!(model::AdvDiffModelMono; t=zero(T))
• update_advection_ops!(model::AdvDiffModelDiph; t=zero(T))

Inputs and callbacks

• D can be scalar or callback (delegated to PenguinDiffusion).
• Velocity inputs (uω, uγ) accept tuple/vector with N components.
• Per-component velocity can be:
  • scalar constant,
  • vector of nodal values (length == cap.ntotal),
  • callback (x...) or (x..., t),
  • Ref to any of the above.

Boundary semantics

• bc accepts diffusion and transport boundary types in one object.
• Internally split by side:
  • diffusion side: Dirichlet, Neumann, Periodic.
  • advection side: Inflow, Outflow, Periodic.
• Dirichlet/Neumann on bc imply advection Outflow at that side.
• Inflow/Outflow on bc imply diffusion homogeneous Neumann at that side.

Notes

• Unknown layout follows layout_mono(cap.ntotal) unless overridden.
• For fixed geometry, solve_unsteady! can reuse a constant assembled operator when data are time-independent.
• For moving geometry, solve_unsteady_moving! reassembles each step.