OpenFOAM guide/Programmer's Guide Errata

Community created Errata for the OpenFOAM Programmer's Guide:

• Online version: OpenFOAM Programmer's Guide at SF.net
• The local version in your installation can be found by running one of the respective commands:
  • On OpenFOAM 3.0 and older, as well as foam-extend and all OpenFOAM+ versions:

    echo $WM_PROJECT_DIR/doc/Guides-a4/ProgrammersGuide.pdf

  • As of OpenFOAM 4, there is no Programmer's Guide. This is now maintained by the OpenFOAM+ project.

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Notes to contributors: Please include the chapter number of the printed version to avoid confusion (the Wiki might give different chapter numbers)

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1 Chapter 1: Tensor mathematics

1.1 Section 1.2: Tensors

As reported in the bug report #1068, there are a couple of references to OpenFOAM 1.x, which is likely an old reference to the original FOAM 2.x version. Feel free to compare to the old documentation at Nabla: the old Programmer's Guide, section 1.2 Tensors.

Either way, feel free to disregard the 1.x reference, since its objective is reflect that tensors as a mathematical entity, are only partially implemented in OpenFOAM.

1.2 Section 1.4: OpenFOAM tensor classes

1.2.1 Subsection 1.4.1: Algebraic tensor operations in OpenFOAM

Valid versions:

In Table 1.2: Algebraic tensor operations in OpenFOAM, the following entries need fixing:

Operation	Description in OpenFOAM (wrong)	Description in OpenFOAM (correct)
Component maximum	max(a)	cmptMax(a)
Component minimum	min(a)	cmptMin(a)
Scale	scale(a,b)	cmptMultiply(a,b)

2 Chapter 2: Discretisation procedures

2.1 Section 2.1: Differential operators

2.1.1 Subsection 2.1.2: Divergence

Valid versions:

(Note: Already fixed in )

The documented divergence operator for tensors is incorrect:

$\nabla \bullet T = \partial_i T_{ij}=\left( \begin{matrix} \frac{\partial T_{11}}{\partial x_1} + \frac{\partial T_{12}}{\partial x_1} + \frac{\partial T_{13}}{\partial x_1}\\ \frac{\partial T_{21}}{\partial x_2} + \frac{\partial T_{22}}{\partial x_2} + \frac{\partial T_{23}}{\partial x_2}\\ \frac{\partial T_{31}}{\partial x_3} + \frac{\partial T_{32}}{\partial x_3} + \frac{\partial T_{33}}{\partial x_3} \end{matrix} \right)$

It should be:

$\nabla \bullet T = \left( \begin{matrix} \frac{\partial }{\partial x_1}, & \frac{\partial }{\partial x_2}, & \frac{\partial}{\partial x_3} \end{matrix} \right) \bullet \left( \begin{matrix} T_{11} & T_{12} & T_{13} \\ T_{21} & T_{22} & T_{33} \\ T_{31} & T_{32} & T_{33} \\ \end{matrix} \right) =\partial_j T_{ji}=\left( \begin{matrix} \frac{\partial T_{11}}{\partial x_1} + \frac{\partial T_{21}}{\partial x_2} + \frac{\partial T_{31}}{\partial x_3}\\ \frac{\partial T_{12}}{\partial x_1} + \frac{\partial T_{22}}{\partial x_2} + \frac{\partial T_{33}}{\partial x_3}\\ \frac{\partial T_{13}}{\partial x_1} + \frac{\partial T_{32}}{\partial x_2} + \frac{\partial T_{33}}{\partial x_3} \end{matrix} \right)$

2.2 Section 2.4: Equation discretisation

2.2.1 Subsection 2.4.6: Gradient

Valid versions:

• All references to timeScheme should be either gradSchemes or snGradSchemes [1].
• The indication of [Check**] implies that this subsection needs to be revised.

2.2.2 Subsection 2.6.1: Physical boundary conditions

Valid versions:

• The indication of [Check**] implies that this subsection needs to be revised.

5 Known forum threads on this topic

This is a unordered list of links to threads about typos and errors in the Programmer's Guide that have been found by the community:

• Bug in the programmer's guide: divergence of a tensor field
  • Documented in Subsection 2.1.2: Divergence, but keep in mind that this has already been fixed.
• In Programmer's Guide p. 40
  • The issues in post #1 are at Subsection 2.4.6: Gradient and Subsection 2.6.1: Physical boundary conditions
• Programmers Guide Bugs
  • The issues indicated in post #1 are already here in the wiki in the subsection Subsection 1.4.1 Algebraic tensor operations in OpenFOAM.
• Error in documentation
  • Only affects