Passive scalar transport
Passive scalar transport in OpenFOAM: tracing where flow carries something
Release a tracer into a converged flow field and follow where it goes — contamination spread, ventilation effectiveness and residence time.
What it is
The scalar is carried by the flow but does not change it: no buoyancy, no reaction, no feedback. That one-way relationship is what makes it cheap, because the flow can be solved once and any number of tracers run against it.
What the application sets up
- A converged flow solution for the scalar to ride on
- Source locations and release rates for the tracer
- A diffusivity, though advection normally dominates it
- Monitoring points where concentration matters
- Concentration fields and time histories at those points
Typical uses
- Contaminant and odour spread through a space
- Ventilation effectiveness and air change rates
- Residence time distribution in a vessel
- Exhaust re-ingestion into an intake
Industries
Sectors where this analysis is routinely asked for.
- HVAC & indoor air
- Cleanrooms & labs
- Environmental
- Safety engineering
What comes out
- Tracer concentration maps
- Ventilation effectiveness
- Residence time distribution
- Exposure along paths
OpenFOAM solvers
simpleFoam
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.