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Compressible VoF

Compressible VoF in OpenFOAM: free surface flow where the gas compresses

Two-phase interface tracking where compressibility matters — trapped air pockets, sloshing with pressurised ullage, and impacts that compress the gas phase.

What it is

Standard VoF treats both phases as incompressible, which stops being true when a gas pocket is trapped and squeezed. Here the gas compresses and its pressure rises accordingly, which is what makes trapped-air cushioning and pressurised tank behaviour come out right.

What the application sets up

  • Properties for both phases, with a compressible gas thermophysical model
  • Initial interface position and gas-space pressure
  • Interface compression controls to keep the surface sharp
  • Transient controls with a Courant limit the interface can live with
  • Pressure output in the gas space as well as interface position

Typical uses

  • Tank sloshing with a pressurised gas space
  • Slamming where trapped air cushions the impact
  • Filling and venting of closed vessels
  • Water hammer and rapid valve closure with entrained gas

Industries

Sectors where this analysis is routinely asked for.

  • Marine & offshore
  • Aerospace fuel systems
  • Pressure equipment
  • Transport of liquids

What comes out

  • Interface motion with gas compression
  • Pressure in trapped gas pockets
  • Slosh loads on walls and baffles
  • Venting adequacy

OpenFOAM solvers

  • compressibleInterFoam

Selected and configured for you from the analysis type. You can still see every dictionary the application writes.

In every tier

This analysis type is in the free build. The free tier limits mesh size to 250,000 cells and solving to one core — not which physics you may use.


On accuracy, plainly.

Every analysis type is exercised end to end on every pass — its case is generated, meshed and run — which establishes that the setup is right, not that the answer matches your geometry. No CFD result is evidence until it is checked against something you trust: a measurement, a hand calculation, or a mesh-refinement study the application will run for you. Treat these results with the judgement you would apply to any CFD you set up yourself.