OpenFOAM blockMeshDict Generator

When to use this OpenFOAM helper

• Use it for tutorial-style boxes, ducts, and one-cell-thick 2D channels.
• Use it when a quick blockMeshDict starter is needed before boundary-condition setup.
• Use it to estimate first-pass cell sizes for Courant-number planning.

How to use

1. Select the solver family, distribution guidance, and relevant case settings.
2. Enter only small dictionary, log, folder-listing, or scalar inputs needed by the helper.
3. Click the explicit action button; default values and typing alone do not generate output.
4. Review warnings, compatibility notes, output text, visual summary, and human-review checklist before copying or downloading.

Input guide

Geometry mode

Rectangular box, 2D channel, or simple duct starter geometry.

Dimensions

Length X, width Y, and height/thickness Z must be positive.

Cell counts

Positive integer counts in each direction; 2D channel mode uses one Z cell.

Grading

simpleGrading values in X, Y, and Z must be positive.

Patch names

Inlet, outlet, wall, and frontAndBack names must be safe identifiers.

Notation

Output explanation

• The output is editable blockMeshDict text targeted to system/blockMeshDict.
• The vertex table lists generated vertex numbering.
• The visual summarizes cell counts and aspect-ratio estimate.

Supported OpenFOAM patterns

• simple rectangular boxes
• one-cell-thick 2D channels with empty front/back patches
• simple duct-like orthogonal block starters

Unsupported patterns

• curved edges
• multi-block topology
• snappyHexMesh
• STL import
• CAD geometry
• mesh-quality execution

Output interpretation

• A generated blockMeshDict describes topology and patches, not verified mesh quality.
• High cell-size ratios or inconsistent empty patches need manual review before solving.

Practical review guidance

• Keep patch names consistent with 0-folder field files.
• Use the Courant calculator with the smallest estimated cell size.

Worked examples

Assumptions

• Inputs are interpreted as plain text or scalar numbers supplied by the user.
• Generated OpenFOAM text is starter guidance, not proof of solver compatibility.
• The installed OpenFOAM distribution and case physics remain the final authority.
• The block is axis-aligned and uses positive dimensions.

Practical guidance

• Run blockMesh and checkMesh locally after reviewing the generated text.
• For complex geometry, use a meshing workflow designed for that geometry.

Common mistakes

• Using empty patches with more than one cell through thickness.
• Renaming mesh patches without updating field boundary entries.
• Ignoring convertToMeters when dimensions are entered in a scaled unit.
• Using a single block for geometry that needs multiple blocks.

Limitations

• The generator does not produce multi-block, curved-edge, wedge, STL, or snappyHexMesh dictionaries.
• The tool does not run OpenFOAM, check syntax with OpenFOAM utilities, or inspect local case folders.
• Distribution-specific dictionary differences may require edits before use.
• Critical engineering work requires validated solver workflows and qualified professional review.

Related workflow links