Dear Rob,nSorry for delay. I am now running a mesh independance test based on the coarse grid and refining x1.5 for 2 more grids. But I see what you mean, perhaps I could use an automatic mesh refinement within Fluent here rather than globally refining the whole region?nAnother thing, it is off the original topic somewhat but I was reading the User Guide and in there it notes that outflow bc's cannot be used with multiphase models. Initially we missed this since we followed the setup details in the published paper we are using for benchmarking. What is the effect of outflow bc's and the Eulerian model?nThanksnn