Velocity defect contours

lopez713 · January 4, 2016, 21:50

Hello everyone,

I am new to this forum and have been trying to run an analysis. I want to be able to achieve a target uniform flow of 0.11m/s. My problems are coming when creating a velocity contours that shows the target average uniform flow velocity. I want my results to look like the first picture but they keep on coming like the second picture. If anyone has any idea how to help me out here it would be extremely appreciated. I am sure the problem is simple enough, if extra details are needed please let me know and I will provide them.

ghorrocks · January 5, 2016, 01:22

Please post an image of your geometry and mesh. Also post your Output file or CCL.

I am certain that your mesh is too coarse - that is almost certainly one problem (it is problem 90% of the time so is a safe guess). But there are probably other problems. When you post further details we can take a look.

lopez713 · January 5, 2016, 02:02

Here is my mesh, the geometry is the same as the pictures stated above. The thickness is 0.1 m. Also, not sure how you to upload the output file so I attached a word document with what I have. Thank you so much for your assistance btw it is sincerely welcomed.

ghorrocks · January 5, 2016, 18:58

I see many problems:

* Your mesh is way too coarse. The central section of your mesh will need to be finer. I have no idea if the jet regions are fine enough as I cannot see them in your mesh.
* You have modelled this as steady state. Are you sure it is steady?
* Also 2D: Are sure it is 2D?
* Also laminar: Are you sure it is laminar?
* You have a reference pressure of 1psi but an outlet pressure of 14.7psi. You should use a reference pressure of 15.7psi and an outlet pressure of 0psi.
* You are setting the velocity-pressure coupling Rhie Chow option. Why are you doing this? Unless you have a good reason to do so leave these settings at the defaults.

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January 5, 2016, 01:22		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	Please post an image of your geometry and mesh. Also post your Output file or CCL. I am certain that your mesh is too coarse - that is almost certainly one problem (it is problem 90% of the time so is a safe guess). But there are probably other problems. When you post further details we can take a look.

January 5, 2016, 18:58		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	I see many problems: * Your mesh is way too coarse. The central section of your mesh will need to be finer. I have no idea if the jet regions are fine enough as I cannot see them in your mesh. * You have modelled this as steady state. Are you sure it is steady? * Also 2D: Are sure it is 2D? * Also laminar: Are you sure it is laminar? * You have a reference pressure of 1psi but an outlet pressure of 14.7psi. You should use a reference pressure of 15.7psi and an outlet pressure of 0psi. * You are setting the velocity-pressure coupling Rhie Chow option. Why are you doing this? Unless you have a good reason to do so leave these settings at the defaults.