How efflux1510/leidenfrost-effect-simulation works
Purpose and Runtime
This is an OpenFOAM-v2106 multi-region CFD case for a liquid-droplet impact on a superheated solid surface. It runs multiRegionPhaseChangeFlow with geometric VOF (PLIC-RDF), conjugate heat transfer, evaporation, and adaptive mesh refinement. The domain models one quarter by symmetry.
Primary entry point: Allrun. Supporting lifecycle scripts are Allclean, run_case.sh, restartcase.sh, and reconstructingMesh.sh.
Region Model and Coupling
The simulation has separate fluid and solid regions declared in constant/regionProperties. Their mesh, fields, numerics, and material definitions remain region-scoped:
• Fluid: constant/fluid/thermophysicalProperties, constant/fluid/phaseChangeProperties, system/fluid/fvSolution
• Solid: constant/solid/thermophysicalProperties, constant/solid/radiationProperties, system/solid/fvSolution
Fluid-solid thermal coupling patches are established after meshing through system/fluid/changeDictionaryDict and system/solid/changeDictionaryDict.
Fluid Physics
The fluid region represents air and water with phase-specific thermophysical inputs in constant/fluid/thermophysicalProperties.air and constant/fluid/thermophysicalProperties.water. Phase change is configured in constant/fluid/phaseChangeProperties; the intended model is Schrage evaporation with a Hardt-Wondra mass source.
Gravity is supplied by constant/g. Turbulence behavior is selected in constant/fluid/turbulenceProperties. Initial and evolving fields reside under time directories, including 0.orig/fluid/alpha.water, 0.orig/fluid/U, and 0.orig/fluid/T.
Mesh and Interface Adaptation
Each region begins as a block mesh: system/fluid/blockMeshDict and system/solid/blockMeshDict. The fluid phase field is initialized as a spherical droplet using system/fluid/initAlphaFieldDict.
Dynamic adaptive refinement targets the liquid-gas interface. Baseline mesh-motion/refinement behavior is in constant/fluid/dynamicMeshDict; staged AMR settings are switched through system/auxiliaryDicts/dynamicMeshDict1 and system/auxiliaryDicts/dynamicMeshDict2. Static/refinement support dictionaries include system/refineMeshDict and system/topoSetDict.
Execution Pipeline
Allrun orchestrates the case in this order:
1. Generate fluid and solid meshes with blockMesh.
2. Apply coupled-patch mappings with changeDictionary.
3. Initialize droplet volume fraction with initAlphaField.
4. Renumber mesh, decompose for parallel execution, and run a short aggressive-AMR pre-run.
5. Apply droplet impact velocity with setFields, driven by system/fluid/setFieldsDict.
6. Run the adaptive transient multiRegionPhaseChangeFlow solve.
The pre-run/main-run control transition is represented by system/auxiliaryDicts/controlDict1, system/auxiliaryDicts/controlDict2, and the active system/controlDict.
Parallel and Numerical Boundary
The intended execution is an 8-processor OpenFOAM parallel job. Decomposition is configured globally and per region through system/decomposeParDict, system/fluid/decomposeParDict, and system/solid/decomposeParDict; fluid load balancing is configured in system/fluid/balanceParDict.
Discretization and solver controls are separated by region in system/fluid/fvSchemes, system/fluid/fvSolution, system/solid/fvSchemes, and system/solid/fvSolution. The repository is a solver case rather than application code; OpenFOAM executables and its parallel runtime are its material external dependencies.
Components 17
Case execution
- Allrun · Orchestrates meshing, setup, pre-run, and transient solve.
Allrun - Regional block meshes
system/fluid/blockMeshDict - Coupled patch mapping · Applied separately to establish fluid-solid thermal patches.
system/fluid/changeDictionaryDict - Droplet initialization
system/fluid/initAlphaFieldDict - Aggressive AMR pre-run
system/auxiliaryDicts/controlDict1 - Impact velocity fields
system/fluid/setFieldsDict - multiRegionPhaseChangeFlow · Parallel transient multi-region phase-change solve.
Fluid region
Air-water VOF, evaporation, and adaptive interface refinement.
- Fluid phases and evaporation · Air/water thermophysics with Schrage and Hardt-Wondra phase change.
constant/fluid/phaseChangeProperties - Fluid initial fields · VOF fraction, velocity, and temperature states.
0.orig/fluid/alpha.water - Interface AMR · Refines the liquid-gas interface with staged settings.
constant/fluid/dynamicMeshDict - Fluid numerics
system/fluid/fvSolution
Solid region
Conjugate heat-transfer solid.
- Solid thermal and radiation
constant/solid/thermophysicalProperties - Solid numerics
system/solid/fvSolution
Controls and parallel
- Region declaration · Declares fluid and solid regions.
constant/regionProperties - Run control transition · Switches from pre-run to main transient controls.
system/auxiliaryDicts/controlDict2 - 8-way decomposition · Global and region decomposition plus fluid load balancing.
system/decomposeParDict
Other components
- OpenFOAM parallel runtime
Connections 23
- Allrun → Regional block meshes: runs blockMesh
- Allrun → Coupled patch mapping: runs changeDictionary
- Allrun → Droplet initialization: runs initAlphaField
- Allrun → Aggressive AMR pre-run: runs after decomposition
- Allrun → Impact velocity fields: runs setFields
- Allrun → multiRegionPhaseChangeFlow: launches main run
- Region declaration → Fluid phases and evaporation: defines region
- Region declaration → Solid thermal and radiation: defines region
- Coupled patch mapping → Solid thermal and radiation: establishes thermal interface
- Droplet initialization → Fluid initial fields: sets alpha.water
- Fluid phases and evaporation → multiRegionPhaseChangeFlow: phase-change physics
- Fluid initial fields → multiRegionPhaseChangeFlow: initial state
- Interface AMR → Aggressive AMR pre-run: drives refinement
- Interface AMR → multiRegionPhaseChangeFlow: adaptive mesh
- Aggressive AMR pre-run → Impact velocity fields: then applies impact
- Impact velocity fields → multiRegionPhaseChangeFlow: initial velocity
- Fluid numerics → multiRegionPhaseChangeFlow: fluid discretization and solvers
- Solid thermal and radiation → multiRegionPhaseChangeFlow: conjugate heat transfer
- Solid numerics → multiRegionPhaseChangeFlow: solid discretization and solvers
- Run control transition → multiRegionPhaseChangeFlow: main-run controls
- 8-way decomposition → Aggressive AMR pre-run: decomposes regions
- 8-way decomposition → multiRegionPhaseChangeFlow: 8 processors
- OpenFOAM parallel runtime → multiRegionPhaseChangeFlow: executes