lift force problem with Flow around a cylinder

Scabbard · April 11, 2014, 15:16

Hi Foamers,

I am trying to simulate a flow around stationary cylinder on Re=20000. I am using the LES pimplefoam. However, every time I get the lift coefficient, the graph like shows in attachedy1.jpg

In my opinion, this graph must have something wrong. But I try to use the high quality mesh, increase the tolerance and time step. It still get the graph like this. Could you give me some recommendations how could I get a stabilize cl graph?

Thank you for your help.

Best wishes

manoj jaiswal · July 11, 2014, 08:31

the graph you have obtained is correct . The cl is calculated for the entire body not for a particular point and so there would be karman vortex shedding and hence the lift would oscillate with time .

Scabbard · July 21, 2014, 05:19

Quote:

Originally Posted by manoj jaiswal

the graph you have obtained is correct . The cl is calculated for the entire body not for a particular point and so there would be karman vortex shedding and hence the lift would oscillate with time .

Dear Manoj,

Thank you for your help.

Best wishes,
Scabbard

April 11, 2014, 15:16	lift force problem with Flow around a cylinder in pimpleFoam	#1
Scabbard Member Join Date: Dec 2013 Location: Newcastle Posts: 54 Rep Power: 13	Hi Foamers, I am trying to simulate a flow around stationary cylinder on Re=20000. I am using the LES pimplefoam. However, every time I get the lift coefficient, the graph like shows in attachedy1.jpg In my opinion, this graph must have something wrong. But I try to use the high quality mesh, increase the tolerance and time step. It still get the graph like this. Could you give me some recommendations how could I get a stabilize cl graph? Thank you for your help. Best wishes Last edited by Scabbard; April 11, 2014 at 16:44.

July 11, 2014, 08:31	cl graph	#2
manoj jaiswal New Member Manoj Jaiswal Join Date: Jun 2014 Posts: 3 Rep Power: 12	the graph you have obtained is correct . The cl is calculated for the entire body not for a particular point and so there would be karman vortex shedding and hence the lift would oscillate with time .

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