The Explosia FX Collider Tag
If you want the simulation to collide with other objects, those objects must have this tag attached to them. A standard X-Particles Collier tag will not work.
The tag's interface looks like this:
Check this switch if the collision object is a closed volume. If using a thin surface such as a Plane object, uncheck it.
Pressure will in effect push the fluid away from the collider object (note that sometimes this has to be of very high value and you may need to increase the 'Max Pressure Iter' value in the simulation tab).
Velocity multiplication increases the velocity of the collision object when it is moving and passes that in to the solver.