[ROY4]

Hello everyone
I used arithmetic average to time average my transient data in CFX. It seemed that it was doing right, and the results were saved in ".trn" format in a directory.
after I opened the CFD-POST to post process my results it showed me all times that I have saved but it seemed the contours were not time averaged, Because in my case which is a bubble column the time averaged results should be like a parabola with maximum point and the air volume fraction should have been focused in the center(5th attachment) but it was not(my result in 4th attachment). I wanted to see if these ".trn" files are time averaged or I should do some thing else and make a setting in CFD Post to get the time averaged results?
I don't know if I'm doing the time averaging process right(1st to 3rd attachments), I once asked here and they said arithmetic average is time averaging, But why it didn't work in my case?
please if any one has any suggestion about this really serious problem help me,
By the way I checked the tutorials and CFX-PRE guide and it didn't give a good explanation about time averaging,
thanks a lot

[ghorrocks]

Rather than blame the averaging I would look at your simulation accuracy. Your results look fundamentally different to the published results and no amount of averaging is going to fix an error of that magnitude. There is something fundamentally wrong with your simulation.

So look at your multiphase setup, boundary conditions, and mesh, time step and convergence toelrances.

[ROY4]

Originally Posted by ghorrocks

Rather than blame the averaging I would look at your simulation accuracy. Your results look fundamentally different to the published results and no amount of averaging is going to fix an error of that magnitude. There is something fundamentally wrong with your simulation.

So look at your multiphase setup, boundary conditions, and mesh, time step and convergence toelrances.

dear ghorrocks,
yeah you are right, I just brought them to show the pattern which is wrong, it is not a parabola that is focused on the center. there are some different charactristics in these two simulations such as bubble diameter and lift coefficient, so of course they won't be the same. I'm doing the validation step by step and it is not exactly the one in the paper yet, SO please check my time averaging.

[ghorrocks]

Your settings appear to have set up averaging, but I cannot tell whether it is correct or not because I cannot know whether the settings you have used are appropriate or not.