I was modelling a 3D cylindrical fluidised bed having a bed of one type of particle, but on running the simulation the particles are modelled on the boundary outside of the cylinder instead of inside. They are also falling downward instead of going with the fluid.
Your STL normals are pointing in the wrong direction:
If you imported the geometry through an STL file:
https://mfix.netl.doe.gov/doc/mfix/20.1.0/reference/faq.html#how-to-verify-flip-stl-file-facet-normals
https://mfix.netl.doe.gov/doc/mfix/20.1.0/tutorials/tutorial_cyclone_sms.html
If you built the geometry with implicit or primitive shapes, apply the “flip normals” filter.
Thank you for replying, my problem of particles coming outside the cylinder is solved but the particles are still settling down and not moving in the direction of fluid.
I know this because velocity in the x-direction is always 0