Integration Resolution
The integrations performed to calculate the flux arriving at a particular element use a computational technique known as the hemicube method, which constructs a 2D view of the other elements from the perspective of each element. The resolution employed is determined by the Integration Settings on the Free Molecular Flow interface node. A larger number indicates a greater integration resolution, and consequently more accurate results. For the results of a model to be accurate the solution should not change significantly when the integration resolution is increased.
For 2D axisymmetric components, the number of Integration Sectors must also be specified. To compute the integrals in an axisymmetric component COMSOL Multiphysics must construct a virtual geometry in three dimensions. The number of sectors in the geometry are determined by this setting. The sensitivity of the solution to this setting should be evaluated.