Gmsh Meshing Export To Aqwa Dat Format

Export to AQWA (.DAT Format) (+4)

Export to AQWA (.DAT Format)

AQWA requires panel meshes in its proprietary .DAT format. gmsh cannot export directly to AQWA format, so a post-processing conversion is needed.

def msh_to_aqwa_panels(msh_file: str, dat_file: str):
    """Convert gmsh MSH to AQWA panel data.

    AQWA expects quad panels (QPPL DIFF cards) with nodes
    defined in counter-clockwise order when viewed from outside.

    See: skills/data/scientific/cad-mesh-generation/SKILL.md

*See sub-skills for full details.*

## Export to WAMIT (GDF Format)


```python
def msh_to_gdf(msh_file: str, gdf_file: str, ulen: float = 1.0,
               gravity: float = 9.81):
    """Convert gmsh MSH to WAMIT/OrcaWave GDF format.

    See: skills/data/scientific/cad-mesh-generation/SKILL.md
    for complete GDF export implementation.
    """
    # GDF format reference:
    # Line 1: header

*See sub-skills for full details.*

## Export to Nemoh/BEMRosetta


```python
def export_for_nemoh(msh_file: str, nemoh_dir: str):
    """Export gmsh mesh for Nemoh solver.

    Nemoh expects mesh in its own format. Use BEMRosetta for conversion:
      BEMRosetta_cl.exe -mesh -i input.msh -o output.dat -f nemoh

    Alternative: export MSH v2.2 and use BEMRosetta CLI.
    """
    gmsh.initialize()

*See sub-skills for full details.*

## MSH v2.2 for BEM Tools


Many BEM tools require MSH v2.2 format (ASCII). Always set:

```python
gmsh.option.setNumber("Mesh.MshFileVersion", 2.2)
gmsh.option.setNumber("Mesh.Binary", 0)  # ASCII
gmsh.write("output.msh")

Quality Targets for Hydrodynamic Analysis

Rule of thumb: Element size <= lambda/7 where lambda is the shortest wavelength of interest.