6.4.2 Non-Conformal Interface Algorithm

In the current version of ANSYS FLUENT, non-conformal interface calculations are handled using a virtual polygon approach, which stores the area vector and centroid of the polygon faces. This approach does not involve node movement and cells are not necessarily water-tight cells. Hence gradients are corrected to take into account the missing face area.

Previous versions of FLUENT (6.1 or earlier) used a triangular face approach, which triangulated the polygon intersection faces and stored triangular faces. This approach involved node movement and water-tight cells, and was not as stable as the current virtual polygon approach. Note that case files in which the interface was set up using FLUENT 6.1 or earlier can be read and run normally in the current version of ANSYS FLUENT, which will use the virtual polygon approach rather than the triangular face approach.

It is possible that distorted meshes may be produced during sliding mesh calculations, generating what are called "left-handed'' faces. You cannot obtain a flow solution until all of the faces are "right handed'', and so ANSYS FLUENT corrects the left handedness of these faces automatically. In extreme cases, the left-handed faces cannot be fully corrected and are deleted automatically, so that the solution does not diverge.

Left-handed cells can also be created for the geometries that contains sharp edges and corners, which may affect the final solution. For such geometries, it is recommended to first separate the zones and then create the interfaces separately to get the better solution.

The additional input of the angle / translation vector at the angle/translation-vector> prompt in the console may be required to recreate face-periodic interfaces. Also, with the current mesh interface algorithm in parallel, there is no need for encapsulation.