Calculating Vorticity

ghorrocks · October 29, 2017, 02:52

Vorticity is a vector field in a 3D simulation. It does not have a single scalar value to plot on a plane as you appear to have done. You might have plotted the magnitude of the vorticity - that will not have negative values by definition and you will not see the odd symmetry which is what I think you are referring to.

Try plotting the correct vorticity component. It should show the odd symmetry.

hamed1983 · October 29, 2017, 03:43

Dear ghorrocks

Many thanks for your replying and explanation but the problem is that how I should to show the odd symmetry in CFX? I mean is it in volume rendering or any option else in CFD post?

Regards
Hamed

ghorrocks · October 29, 2017, 05:54

You have to show a vorticity component (X, Y or Z) on your plane.

hamed1983 · October 29, 2017, 06:42

Dear Ghorrocks

I have done what you advised and plotted the vorticity by component so the results are attached but I do not know whether are they really correct or not? would I please to take a look at them and guide me.

Best Regards

hamed1983 · October 29, 2017, 07:02

One thing else is these are results for logarithmic color scale and for linear color scale the results became like the attached

ghorrocks · October 29, 2017, 07:14

Doesn't the X and Z components show what you are looking for?

hamed1983 · October 29, 2017, 08:24

These are the latest results that i have achieved but I want to know are they correct?

Regards,

ghorrocks · October 29, 2017, 18:35

Good question. See FAQ: https://www.cfd-online.com/Wiki/Ansy...publishable.3F and https://www.cfd-online.com/Wiki/Ansy..._inaccurate.3F

hamed1983 · October 29, 2017, 19:02

many thanks, The results seems correct but lastly I wish to have a render for total vorticity like the attached photo I saw in another paper I have seen and I do not know how. So I appreciate if you can guide me.

regards,

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
vorticity boundary condition	bearcharge	Main CFD Forum	0	May 14, 2010 12:32
vorticity calculation at symmetryplane	benconnell	OpenFOAM	0	April 14, 2009 19:45
Vorticity Iso-Surface	John	Main CFD Forum	0	April 5, 2009 00:10
Problems in calculating the fluid traction on the current structure frame in 3D models	fw407	OpenFOAM Running, Solving & CFD	0	August 6, 2008 13:04
How to update polyPatchbs localPoints	liu	OpenFOAM Running, Solving & CFD	6	December 30, 2005 18:27

October 29, 2017, 02:52		#21
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Vorticity is a vector field in a 3D simulation. It does not have a single scalar value to plot on a plane as you appear to have done. You might have plotted the magnitude of the vorticity - that will not have negative values by definition and you will not see the odd symmetry which is what I think you are referring to. Try plotting the correct vorticity component. It should show the odd symmetry.

October 29, 2017, 03:43		#22
hamed1983 New Member Hamed Join Date: Mar 2017 Location: Iran Posts: 29 Rep Power: 9	Dear ghorrocks Many thanks for your replying and explanation but the problem is that how I should to show the odd symmetry in CFX? I mean is it in volume rendering or any option else in CFD post? Regards Hamed

October 29, 2017, 05:54		#23
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	You have to show a vorticity component (X, Y or Z) on your plane.

October 29, 2017, 07:14		#26
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Doesn't the X and Z components show what you are looking for?

October 29, 2017, 18:35		#28
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Good question. See FAQ: https://www.cfd-online.com/Wiki/Ansy...publishable.3F and https://www.cfd-online.com/Wiki/Ansy..._inaccurate.3F