Where are the vortices?

boffin5 · February 12, 2021, 20:16

Hi from a new member and a new Openfoam user. I am finally up and running, and succeeded in running a case with an airfoil fitted with a gurney flap. For guidance, I used the airfoil2D case in the tutorials. Attached is a screenshot of the flow tracer. My question is regarding the absence of the vortices that I expected to see. Is this because the simpleFoam solver is not sophisticated enough for vortical flow? How do I proceed to capture this more advanced flow?SnapCrab_NoName_2021-2-12_15-24-55_No-00.png

Bazinga · February 13, 2021, 04:12

simpleFoam should be able to capture a steady state solution of the vortices in the wake. In my experience, you would need to move the line that enables showing of streamlines just behind the back of your geometry.

boffin5 · February 15, 2021, 20:27

Thanks Bazinga,
I tried moving the seed line for the streamlines as you suggested, but there are still no vortices. I have carefully compared all of my setup files to the tutorial, but haven't found any differences. Help! I really need to get to the bottom of this!
boffin5

shock77 · February 16, 2021, 05:03

Your velocity range is quite low. Did you manually adjust the range? Or are your velocities that low? 0.1 m/s?

February 12, 2021, 20:16	Where are the vortices?	#1
boffin5 Senior Member Alan w Join Date: Feb 2021 Posts: 310 Rep Power: 7	Hi from a new member and a new Openfoam user. I am finally up and running, and succeeded in running a case with an airfoil fitted with a gurney flap. For guidance, I used the airfoil2D case in the tutorials. Attached is a screenshot of the flow tracer. My question is regarding the absence of the vortices that I expected to see. Is this because the simpleFoam solver is not sophisticated enough for vortical flow? How do I proceed to capture this more advanced flow?SnapCrab_NoName_2021-2-12_15-24-55_No-00.png

February 15, 2021, 20:27	Still no vortices	#3
boffin5 Senior Member Alan w Join Date: Feb 2021 Posts: 310 Rep Power: 7	Thanks Bazinga, I tried moving the seed line for the streamlines as you suggested, but there are still no vortices. I have carefully compared all of my setup files to the tutorial, but haven't found any differences. Help! I really need to get to the bottom of this! boffin5

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February 13, 2021, 04:12		#2
Bazinga Senior Member Join Date: Jun 2012 Location: Germany, Bochum Posts: 230 Rep Power: 17	simpleFoam should be able to capture a steady state solution of the vortices in the wake. In my experience, you would need to move the line that enables showing of streamlines just behind the back of your geometry.

February 16, 2021, 05:03		#4
shock77 Senior Member Join Date: Dec 2019 Posts: 215 Rep Power: 8	Your velocity range is quite low. Did you manually adjust the range? Or are your velocities that low? 0.1 m/s?