Centrifugal forces

[JuhaHo]

I'm feeding particles inside a horizontally rotating cylindrical object with small radial wall sections. I wonder what is the best way to reduce centrifugal forces. The particles are not falling down when they are hanging upside down. I want the particles to start falling at 60 degrees, but the centrifugal forces are pushing them tightly to cylinder walls.

I want to reduce the "red arrow" force, so particles can fall freely
.