Hello Rob. Thanks for your question. As I explained we are talking about billions of particles whose size is in the order of a few microns. nThe Euler model does not give a final resting status in which two phases have been separated due to gravity. Keep in mind that we start from a uniform suspension with volume fraction 0.4. The things mix and mix for ever. Since the domain is a closed one (no inlet or outlet) , you get spurious circulation of the flow for ever. Something similar to natural convection. nIn