Rob
Ansys Employee
Read up on the DPM maths as that'll explain what's going on, and why nothing visibly changes in the flow field. nMPM is an older model and may be lacking some of the additional UDF hooks to add to the momentum. Check what you need to do as you may find you can add momentum another way:gravity doesn't have to be constant or down in a CFD model! All I can say on the model is read the documentation: I've seen it used but never tried to switch it on.nThe most comprehensive method is probably 6DOF moving mesh with some additional UDFs to account for contact with the pipe walls. There are some examples in the UDF documentation and videos in the general help. n