Backward Compatibility with Version 4.3a

Heat Transfer in porous media

Old models using the Porous feature will be supported in the COMSOL Multiphysics interface. However, it is recommended to replace this feature with Heat Transfer in Porous Media (see Obsolete Features and Variables). For a model using the API, it will be necessary to update the model to use Heat Transfer in Porous Media.

Surface-to-surface radiation

The surface radiosity, previously named J, is now named ht.J by default (assuming that ht is the physics interface tag).

Models created using versions 4.3 and 4.3a that contain surface-to-surface radiation support the old syntax in multiphysics interfaces. It is, however, recommended that you update the models to use the new syntax. Models created in a version before 4.2a need to be opened in version 4.3 or 4.3a and resaved before being opened in 5.0 or a later version.

For a model using the API, you must update the model to use the new syntax.

Radiation in Participating Media

The radiative intensity variable names, previously named I1 and so on, became ht.I1 (when there are fewer than 10 discrete directions) or ht.I01 (when there are 10 or more discrete directions) by default.

Models created in versions 4.3 and 4.3a that include radiation in participating media support the old syntax in multiphysics interfaces. It is, however, recommended that you update the models to use the new syntax. Models created in a version before 4.2a need to be opened in version 4.3 or 4.3a and resaved before being reopened in 5.0 or a later version. In addition, for all versions, it may be necessary to regenerate the default solver to get the correct solver settings.

The S2 quadrature in 2D has been replaced by the LSE symmetric quadrature. It has been updated so that it coincides with the other quadratures. LSE symmetric quadratures were already used for S4, S6, and S8 in 2D and for all 3D quadratures. This quadrature update can result in significant changes in 2D models using the S2 quadrature. However, the theoretical error is not different and the 2D and 3D implementations are now consistent.