Abdelmadjid Belmokhtar

Thank you very much for your reply. I think that the sine curve can tell me that the flow cannot be supposed as steady. And about choosing the SST model, I based it on the results of a work which compares the simulation of a single-phase flow in a Cyclone Gasifier using different turbulence models with the experimental results. They found that the SST model can be a good choice. Of course, LES is the preferred choice to predict phenomena, but it takes a long time