symmetry vs. slip Bounday condition

syoon · April 28, 2009, 07:45

I'm not quite sure what is the difference between symmetry boundary condition and slip boundary condition.

According to my understanding, both of them applies zero to normal component and zero gradient to tangential component. dont' they?

Then, what is the difference?

Regards,
Sungho

Anne Lincke · February 22, 2012, 07:15

Hey,
I am asking myself the same question.
Is there an answer already?

Kind Regards
Anne

FelixL · February 22, 2012, 08:20

Hi, there,

the slip and symmetry BCs are numerically the same.

There can be a difference in how OpenFOAM treats these boundaries in pre- and post-processing, respectively. I.e. slip can be applied to wall-type-boundaries and the wall-only post-processing applications (wallGradU for example) can still be used.

Greetings,
Felix.

Anne Lincke · February 22, 2012, 09:15

Thank you for this fast answer, Felix!

hhh · August 30, 2012, 10:07

Dear friends,
i am doing 3D wing analysis, i have doubt on boundary conditions in fluent ie both symmetry and periodic, anybody have the answer please let me know briefly,for what kind of purpose to use symmetry & periodic boundary conditions, please tell any example with problem.

s.m · April 30, 2013, 03:01

Quote:

Originally Posted by FelixL

Hi, there,

the slip and symmetry BCs are numerically the same.

There can be a difference in how OpenFOAM treats these boundaries in pre- and post-processing, respectively. I.e. slip can be applied to wall-type-boundaries and the wall-only post-processing applications (wallGradU for example) can still be used.

Greetings,
Felix.

hi Felix,
would you please explain us more; about how difference OpenFOAM treats these boundaries (symmetry and slip)?
thank you very much

i have an airfoil, i set the inlet boundary velocity inlet, and the outlet boundary pressure outlet, i doubt about defining the up and down surface of my airfoil symmetry or slip?
thanks a lot again Felix.

kkpal · December 14, 2018, 23:46

I can understand symmetry on a plane patch. But if slip is identical to symmetry condition, what does it mean to use slip on a curved or a closed surface, like a circular cylinder?

April 28, 2009, 07:45	symmetry vs. slip Bounday condition	#1
syoon New Member sungho yoon Join Date: Mar 2009 Posts: 20 Rep Power: 17	I'm not quite sure what is the difference between symmetry boundary condition and slip boundary condition. According to my understanding, both of them applies zero to normal component and zero gradient to tangential component. dont' they? Then, what is the difference? Regards, Sungho

February 22, 2012, 08:20		#3
FelixL Senior Member Felix L. Join Date: Feb 2010 Location: Hamburg Posts: 165 Rep Power: 18	Hi, there, the slip and symmetry BCs are numerically the same. There can be a difference in how OpenFOAM treats these boundaries in pre- and post-processing, respectively. I.e. slip can be applied to wall-type-boundaries and the wall-only post-processing applications (wallGradU for example) can still be used. Greetings, Felix. kiddmax, fumiya, hua1015 and 13 others like this.

August 30, 2012, 10:07	boundary condition (symmetry vs periodic doubt)	#5
hhh Senior Member kunar Join Date: Nov 2011 Posts: 117 Rep Power: 15	Dear friends, i am doing 3D wing analysis, i have doubt on boundary conditions in fluent ie both symmetry and periodic, anybody have the answer please let me know briefly,for what kind of purpose to use symmetry & periodic boundary conditions, please tell any example with problem.

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February 22, 2012, 07:15		#2
Anne Lincke Senior Member Anne Gerdes Join Date: Aug 2010 Location: Hamburg Posts: 168 Rep Power: 16	Hey, I am asking myself the same question. Is there an answer already? Kind Regards Anne

February 22, 2012, 09:15		#4
Anne Lincke Senior Member Anne Gerdes Join Date: Aug 2010 Location: Hamburg Posts: 168 Rep Power: 16	Thank you for this fast answer, Felix!

December 14, 2018, 23:46		#7
kkpal Senior Member Join Date: Jan 2013 Posts: 135 Rep Power: 13	I can understand symmetry on a plane patch. But if slip is identical to symmetry condition, what does it mean to use slip on a curved or a closed surface, like a circular cylinder?