In versions 6.3 and earlier, the default behavior was to allow all particles interacting with the walls to influence the accumulated heat source variables. This behavior corresponds to the Particle–wall interactions option in the
Accumulate over list. However, the default selection for the
Accumulate over list in version 6.4 is
Particles in boundary elements, with which the accumulated heat source is only affected by the particles that freeze or stick to the walls.
If a model built in version 6.3 or earlier is opened in version 6.4, the old default settings are maintained for the Heat Source features that already exist in the model. However, if a new
Heat Source feature is added to the same model in version 6.4, the new default settings will be applied.