http://www.dem-solutions.com/support/files/examples/FluidDrag.zip
This simulation has foam balls being blown by a vertically mounted fan to demonstrate the use of a particle body force.

Please take a look at the code for your own project and remember to come back and post up any modifications or code snippets which will help other users along the way. Feel free to use this forum for asking questions about this contact model.
DEM Solutions Team.