[paru]

I am simulating flow through an axial pump (by specifying total pressure at inlet and static pressure at outlet), so bulk of the flow is moving in the axial direction. I observe some spurious vectors in the blade tip gap and swirl at the interface between rotating and stationary domain. Also the flow rate is much less than measured value. For a coarse mesh, when I turned on the alternate rotation method, it seemed to correct the flow vectors and the flow rate value. However, with a fine mesh, the swirl continues to exist and the simulation gives a low flow rate despite turning on the alternate rot method. Kindly help me understand what's happening!

[Gert-Jan]

We need a screendump to really make a good comment.
However, a mistake people quite often make is that they judge this kind of simulation by looking at the vectors and flow with variable "Velocity". I suggest to look at "Velocity at Stn Frame"