I have a sphere doing simple sin animation along the Y axis. While filling the sphere with particles i also turn it into a collision volume with inverted sign so that it will act like a sphere container for my flip object. But when the simulation begins, the flip particle “disappeared” along the way, see attachments.

First, i think it's because of sub steps, so i increased both the sub steps in the dop network and the flip solver(receeding is off), but that didn't help, because the animation is not a fast one, with a expression like this “sin($T*20)*1”, and the sphere radius is 0.1.

I couldn't figure out what is the problem, any ideas?

You may want to check out the video at this link. Guarav demonstrates a similar approach to containing fluid inside a boundary that is in motion.
http://forums.odforce.net/topic/23631-minute-houdini-tips/ [forums.odforce.net]

Enivob
You may want to check out the video at this link. Guarav demonstrates a similar approach to containing fluid inside a boundary that is in motion.
http://forums.odforce.net/topic/23631-minute-houdini-tips/ [forums.odforce.net]

Thanks for the link, really helpful!