I wish to understand in more detail what Comsol is doing to my equations when using the conservative form in the advanced physics settings in transport of diluted species. On the surface, it seems like it reverses the incompressibilty assumption and places the convective term back into the divergence operator. This cannot be the whole situation, what is going "under the hood" of Comsol? The time-stepping seems to be very small and dynamic, is this the main difference between the two forms?
David