Molecular Flow Module Updates

For users of the Molecular Flow Module, COMSOL Multiphysics® version 6.1 offers a new feature for identifying planes of reflection symmetry and applying sector symmetry. Read more about this update below.

Improved Symmetry Condition for Free Molecular Flow

A new Symmetry global condition for the Free Molecular Flow interface extends the capability of the Plane Symmetry node that was available in previous versions. In 2D, it is now possible to specify either a single symmetry plane or two orthogonal planes. In 3D, it is now possible to specify either one, two, or three symmetry planes as long as all of the planes are mutually orthogonal.

With this feature, you can now also apply sector symmetry to your models. This can be done in two different ways: by selecting the boundaries in the start plane and end plane of a single sector (or unit cell) of the symmetric geometry or, when the model geometry is assumed to be one half of a single sector, by selecting the start plane and a reflection plane.

A 3D model with six sectors where five are transparent and one is solid. Example of 6-fold sector symmetry, modeled using the Free Molecular Flow interface. The transparent sectors are not explicitly part of the model geometry.