Meshes

MachLine operates on unstructured meshes and can read in several different formats.

General Tips

MachLine meshes should be watertight. One exception to this is in supersonic flow. Since influences do not propagate upstream in supersonic flow, aft-facing blunt faces (such as the base of a missile) may be left open (unpaneled), and the solution quality will not be negatively affected. In all other cases, supplying a non-watertight mesh to MachLine may result in poor results.

Currently, thin-wing representations are not possible in MachLine due to how Dirichlet boundary conditions function. Thus, all meshes should represent solid bodies with a clearly-defined interior. The interior direction is opposite the panel normal vector. The panel normal vector is oriented in the right-hand direction with respect to the ordering of the panel vertices in the mesh file.

MachLine can only handle triangular panels. Mesh files containing higher-order polygons will be rejected.

While meshes for MachLine are not structured, the arrangement and size of panels in the mesh should be fairly regular. Significant irregularities in the mesh may cause erroneous flow predictions.

Allowable Mesh Types

For all these mesh types, MachLine is only able to read in ASCII. Binary files are not currently allowed.

The following mesh types may be given to MachLine:

• VTK (versions 3, 4, and 5) Certain types of .vtk files define multiple points per line in the POINTS section. MachLine does not detect this, and so such mesh files are not allowed. The .vtk file should have only one point defined per line.
• STL
• .tri