OpenFOAM guide/Interpolation (OpenFOAM)

This article is about Interpolation in OpenFOAM. For other uses, see Interpolation (disambiguation).

OpenFOAM has a number of interpolation methods available. Some are classes that exist for the purpose of interpolation, such as interpolateXY; whereas others use interpolation in their code, such as specieThermo.

1 Main OpenFOAM library

Interpolation available in the main OpenFOAM library includes:

• GGIInterpolation (for General Grid Interfaces, OpenFOAM-extend only);
• interpolateXY (X-Y function interpolation);
• interpolationTable (temporal interpolation);
• patchToPatchInterpolation (for multi-region domains, OpenFOAM-extend only);
• primitivePatchInterpolation (spatial interpolation between points, faces and edges for a primitive mesh);
• RBFInterpolation (used by the Radial Bias Function mesh motion solver, OpenFOAM-extend only);

2 finiteVolume library

Interpolation available in the finiteVolume library includes:

• interpolation (by cell) - interpolation to an arbitrary positions within a specified cell, used by:
  • Lagrange particle tracking (member of solidParticle); and
  • sampling (used in meshToMeshInterpolation);
• surfaceInterpolation - interpolate volume field to face field;
  • $\left . \phi \right \vert_{v\to f}$
  • code: fvc::interpolate(phi);
• pointVolInterpolation - interpolate point field to volume field;
• volPointInterpolation - interpolate volume field to point field;

The last two are an extension of primitivePatchInterpolation to finite volume: a primitive mesh does not have cell centres.

3 sampling library

Interpolation available in the sampling library includes meshToMesh interpolation.

4 Other interpolation

Other forms of interpolation exist in OpenFOAM, such as:

• in the finiteArea library - for finiteArea discretization;
• in the tetDecompositionFiniteElement library - for finite element discretization; and
• in specieThermo, for interpolating thermodynamic properties to curves.