I might have been exaggerated in my attached drawing, but I am expecting to have 4 twist as there are 4 fins inside the fluid domain to assist in the swirling action. The default steps was 500, I have now increased it up to 99999, but still, the pathlines look almost the same with just a few additional lines and only a few of them manage to complete one twist. So, i'm guessing this method doesn't work.nDue to student license limitation and also the geometry (fins inside water domain), I am currently using quite a rough tetra mesh with 3 inflation layers on every surface. O-grid might be hard to implement, as the fins are blocking the path for sweep. I have tried hexa dominant, but it doesnt really catch any detail for the boundary layers. Given that this domain is in a hollow cylinder shape, I'd say O-grid has the same meshing as polar mesh.nHowever let me try meshing with O-grid again or even remove the fins altogether. This might cause inaccurate result, but anyhow, this water domian is my secondary concern. As long as it reduce the temperature of my gas domain even more, how the fluid flows inside can be ignored. In my opinion as a newbie in this field...Arrayn