[spy_hzdr]

Dear all, I am simulating the bubbly flow in stirred tanks with Transient Rotor/Stator boundary for the interface that connects the rotating and still zone. In post-processing, I noticed that the velocity in stn Frame profile is discontinuous when crossing the interface.
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I assume that this discontinuous feature is caused by the different relative coordinate system that applied for each zone. The Trnavg operation in the rotating zone is not performed for an still cell but the cell that rotating in each time step. My question is, would it be possible for us to get the Trnavg results for one still line/surface in the rotating zone in order to justify our simulation with experiment data that obtained by the Eulerian-type instruments (e.g. PIV, LDV)?

[ghorrocks]

Please put images in the post. Here is how: https://www.cfd-online.com/Wiki/Ansy...n_the_forum.3F

The discontinuous feature you note is probably related to the averaging process as you state. Have a look at the velocity field to check this. It could also be caused by insufficient mesh resolution at the interface, or too big time step, or inadequate convergence.

To get averages along a line which is stationary but in a rotating frame of reference: I would do this in post-processing in CFD-Post. It is quite simple to evaluate the conditions along a line at a time step and export the results. Then advance to the next time step and repeat for all time steps. To automate this process use a session file in CFD-Post. Load up all the exported files in some maths capable software (matlab, python, excel, whatever) and perform the averaging.