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Solver Modules

FVM discretization, SIMPLE algorithm, TDMA solver, convergence acceleration.

mod_prop.f90 — property

Updates material properties (viscosity, diffusivity, density) based on temperature and phase state. Three regimes: solid, mushy, liquid. Powder cells use reduced properties. When species_flag=1, uses composition-weighted mixing via mix().

mod_bound.f90 — boundary

Boundary conditions for all equations:

  • Enthalpy: radiation + convection (top), convection (sides/bottom)
  • Momentum: Marangoni stress at free surface (thermal + solutal), no-slip elsewhere
  • Pressure correction: zero in solid region

mod_discret.f90 — discretization

FVM discretization using power-law scheme:

  • discretize_momentum(idir) — u/v/w momentum with staggered grid interpolation
  • discretize_enthalpy(...) — energy equation with delt for transient term
  • discretize_pp() — pressure correction equation

mod_sour.f90 — source

Source terms:

  • Momentum: Darcy resistance (mushy zone), buoyancy (Boussinesq), solid zeroing
  • Enthalpy: volumetric laser source (Gaussian), latent heat, latent heat advection
  • Pressure: mass conservation assembly

mod_entot.f90 — entotemp

Inverts enthalpy → temperature relationship. Handles solid/mushy/liquid regimes. When species_flag=1, uses composition-dependent H-T curve via mix(). Contains only enthalpy_to_temp (prediction logic has been moved to mod_predict.f90).

mod_solve.f90 — solver

  • tdma_solve_3d_2(...) — OpenMP line-by-line TDMA with double k-sweep and per-thread buffers
  • solution_uvw/enthalpy(...) — convenience wrappers
  • cleanuvw() — zeros velocity in solid cells and above boiling point

mod_converge.f90 — convergence

Block correction: accumulates j-k plane coefficients into 1D system along x, solves with TDMA. Reduces low-frequency errors.

mod_revise.f90 — revision

SIMPLE pressure-velocity correction: updates velocity from pressure correction field.

mod_resid.f90 — residue

Residual computation for convergence monitoring: enthalpy, mass, momentum (weighted by reference values).

mod_flux.f90 — fluxes

Energy balance: boundary losses on all 6 faces, heat accumulation, energy ratio for convergence checking.