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Old   March 3, 2005, 04:43
Default volume meshing-Urgent
  #1
emml
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Hi everyone, I have a problem with meshing. I am a new starter and have gone through a model that has two volumes with an upper partition and a lower one, In practice thats how it should be. I have been able to export the mesh for the volumes into fluent but its taken ages to converge. has anybody got a clue what am doing wrong and how i can get the best out put? Thank you
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Old   March 3, 2005, 11:02
Default Re: volume meshing-Urgent
  #2
Jason
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Need much more information on your problem before anyone can help...

What is it you're analyzing? Different things require different techniques to solve...

Structured or Unstructured grid. Did you check your max skewness?

It might not be your mesh, could be your solver settings. Steady or unsteady? Which solver are you using (2D, 2D axi, 3D)? What solver settings are you using (did you modify the URF's, which discretization settings are you using)? What material, and if it's a gas are you using constant density, ideal gas, etc... Turbulent, laminar, or inviscid? Need as much info as you can give on your boundary conditions as well. Also, did you model everything in meters? If not then you have to change your model scale.

Jason
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Old   March 3, 2005, 16:35
Default Re: volume meshing-Urgent
  #3
Manoj Kumar
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hi I want to use structured meshing scheme to mesh my doman. could u pls look at it http://www.geocities.com/kmanoj_cool/btp/mesh.html and help me. which scheme should i use ? i have tried all (copper, map, submap .. ) . but didn't succeed. will i have to slice the volume.

Thanks in advance manoj
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Old   March 3, 2005, 17:12
Default Re: volume meshing-Urgent
  #4
Jason
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Well, the mesh itself looks reasonable, depending on what the mesh looks like near those little walls you have in the front and back of your domain. If those aren't absolutely needed, then get rid of them! If you need them, then you might have to refine the mesh in that area (I'm guessing at what the mesh looks like there based on how it's growing from your body).

When you're using velocity inlets, you should combine it with a pressure inlet/outlet. For your case I would use a velocity inlet upstream of your body and a pressure outlet downstream of your body. I'm not particularly a fan of velocity inlets at all, I would recommend using a pressure inlet in the front and pressure outlet in the back, but that's just my preference.

As far as meshing this body with a structured mesh, you're going to have a difficult time. You're going to have to find a way to break the geometry up so that Gambit thinks you're dealing with more of a rectangular body. I'm e-mailing you a quick pic to try and describe what I'm talking about.

Hope this helps, and goodluck, Jason
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Old   March 4, 2005, 07:16
Default Re: volume meshing-Urgent
  #5
Manoj kumar
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hi Jason Thank u so much. I am trying to work it out as you have said. Your mail is helping me a lot.

Manoj
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Old   March 4, 2005, 19:14
Default Re: volume meshing-Urgent
  #6
zxaar
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check the interfaces, it may happen that your volumes are not connected .. this you could make out from the post processing of the results ... just view all the walls ..and u will see the wall at the place of interfaces .. if so connect them .. otherwise it should converge
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Old   March 4, 2005, 19:17
Default Re: volume meshing-Urgent
  #7
zxaar
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you need it for btp .. which iit you are in ... iitd ??? who is ur guide,

anyway .. to make the structured mesh for the reason you want ..will be difficult .... you can think of using untructured mesh in some portions ..your life will be easy ..
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Old   March 5, 2005, 06:33
Default Re: volume meshing-Urgent
  #8
Manoj Kumar
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hi I am final year student in IIT Madras and ya this is my btp. My guide is Dr. Anantha Subramanian.

I have only one volume. To what extend convergence depends on the mesh, if other inputs are same?

Thanks Manoj
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Old   March 9, 2005, 09:54
Default Re: surface meshing-Urgent
  #9
faiza mahi
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HI i have a difficulte problem for simulate drop-2D with software -Gambit fo mesh&Fluent for simulate. the problem is the model who i take it.i take (wireframe-fluid)rectangle and on it ellipse(of drop of fluid). can you shwo me an idea. Thank's
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