I am simulating gas-particle cyclone and used velocity inlet, pressure outlet for top and bottom outlet with zero,RSM solver. Problem are hard to converge and velocity in the cyclone is not good.

Can anybody give me some advice for boundary ccondition solver?

thanks.

Have a look at the following article (available on the CFX community pages): Mathematical modelling and experimental validation of flow in a cyclone C A Montavon, H Grotjans, I S Hamill, H W Phillips and I P Jones BHR Conference on Cyclone technologies - Warwick 31 May – 2 June, 2000. CFXTP00208

Using RSM on a hydrocyclone calculation will require a transient run as the vortex will tend to twist (in real life also). This will greatly affect your convergence when doing a steady state run. A k-eps run will probably converge fine (non-physical result I would say)

Thanks. I will try.