# symmetry boundary condition in fluent

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 April 12, 2010, 02:54 symmetry boundary condition in fluent #1 New Member   Vahid Memar Join Date: Dec 2009 Posts: 15 Rep Power: 16 Hi I want analysis a 3D fan in fluent but I want to model only one of two blades(the fan has two blade) , but when I use symmetry boundary condition, the solution does not converge. and I think it is logic because in fan we do not have symmetry condition , rather we have rotation axis , but in 3D we can not use axis condition. is any body can help me ?

 April 12, 2010, 07:16 #2 Senior Member   Max Join Date: Mar 2009 Posts: 133 Rep Power: 17 As you already realized, there is no symmetry condition for your given flow problem. Maybe a rotationally periodical boundary condition can be utilized to reduce the computational domain to a 180° segment? cheers

 April 12, 2010, 07:57 #3 New Member   Vahid Memar Join Date: Dec 2009 Posts: 15 Rep Power: 16 How can do rotationally periodical boundary condition on my problem ?

 April 12, 2010, 09:26 #4 Senior Member   Max Join Date: Mar 2009 Posts: 133 Rep Power: 17 It depends on the periodicity of your actual geometry and flow field. Have a look at the UserGuid chapter 7.15 whether periodic bc are applicable for your problem. If so, you have to obey some rules when generating the mesh in gambit (mesh hardlink). cheers

 April 14, 2010, 03:45 Fluent Err #5 New Member   Vahid Memar Join Date: Dec 2009 Posts: 15 Rep Power: 16 Hi Cogline I do hardlink mesh and after that exported mesh, but when I import in fluent , we have an Error , can you guess what is the problem ? you can receive mesh file and gambit file(dbs) from below link. http://ifile.it/voabcxt/Gambit.rar thanks Memar Last edited by v_h_memar; April 14, 2010 at 04:11. Reason: Attaching file

 April 14, 2010, 04:06 #6 Senior Member   Max Join Date: Mar 2009 Posts: 133 Rep Power: 17 Which error?

April 14, 2010, 04:13
#7
New Member

Vahid Memar
Join Date: Dec 2009
Posts: 15
Rep Power: 16
Quote:
 Originally Posted by coglione Which error?
http://ifile.it/voabcxt/Gambit.rar

 August 30, 2012, 09:08 boundary condition (symmetry vs periodic doubt) #8 Senior Member   kunar Join Date: Nov 2011 Posts: 117 Rep Power: 14 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.

May 1, 2019, 00:08
Hi dears Friends
#9
New Member

tea restiana
Join Date: Apr 2019
Posts: 2
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I simulate 3d seawater in the case of dispersion thermal analysis of the power plant cooling water using ansys fluent, the geometry and namely boundary conditions that I modelled is shown in the figure bellow. In modelling physical models used k-epsilon and active energy. the material used is only one phase, namely water. Temperature normal seawater set 30℃ and temperature discharge outlet 37℃.The boundary conditions are discharged outlets, ambient inlet, outlet, ocean, seabed and seashore. The discharge outlet is the discharge area of the cooling water power plant modelled as an inlet velocity with a velocity of 1.71 m / s and a temperature value of 37℃, the ambient inlet boundary condition is modelled as an inlet velocity at 0.4 m / s and a temperature value of 30℃.Outlet modelled as outflow.Seabed and seashore as a wall.
For ocean boundary conditions I model as symmetry. what I want to ask, in my case is it okay if I model ocean as symmetry? Can anyone explain that? Or do I need to use other boundary conditions?
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