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Old   April 30, 2008, 09:58
Default central difference method
  #1
sudhir
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hi,

is it possible to solve heat transfer problem involving only energy transfer using central differencing scheme? usually we have 1st order upwind scheme,2nd order differencing scheme,etc.,there is no central differencing scheme option in fluent. anybody encountered such problem?

thanks
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Old   April 30, 2008, 14:36
Default Re: central difference method
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Paolo Lampitella
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If i'm not wrong, under the tui you can go in:

solve/set/expert

at the third question:

"Allow selection of all applicable discretization schemes?"

Answering "y" should make always available the central differencing scheme.

However, the diffusive fluxes are always discretized with central differencing scheme in Fluent (you can't choose other schemes, it would be a wrong selection) and if you're trying to simulate the conduction in solids there is no other flux so the question has no sense. The only flux for which is available the selection of the discretization scheme is the convective one. In this case you can use the procedure suggested to activate the selection of the central scheme (usually available only under 3d LES)
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Old   May 3, 2008, 02:18
Default Re: central difference method
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sudhir
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hi paolo

thanks for ur reply. i will try the procedure u explained above. asap i will let u know abt my improvements. thanks again.

truly

sudhir
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Old   May 3, 2008, 12:02
Default Re: central difference method
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sudhir
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hi paolo,

i tried like you said but there is no option available in my software as u mention above.i am using FLUENT 6.1... which version are you using?

truly sudhir
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Old   May 4, 2008, 11:06
Default Re: central difference method
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Paolo Lampitella
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Hi,

i have the 6.3.26 and i don't know if there really is some difference in this.

Another way to do that is to activate te LES which will enable the central scheme. If you are doing a 2d simulation you can type the following (all):

(rpsetvar 'les-2d? #t)

and press enter. This will activate the LES (you have to choose it as viscous model with cs = 0) in 2d and so you will be able to select again the central scheme.

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Old   May 5, 2008, 13:08
Default Re: central difference method
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sudhir
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hi

thanks for your reply.for your information there is some difference between fluent 6.1 and fluent 6.3 , especially options available in fluent 6.3 . i have installed fluent 6.3 in my computer. my model is in 2D so i will try the steps you mention above.

truly sudhir
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Old   May 6, 2008, 09:17
Default Re: central difference method
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sudhir
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hi

i am simulating a cylindrical model containing phase changing material(PCM).i am changing wall temperature therby reducing the temperature of hot PCM.there is no flow of fluid..its stationary.will the above steps mentioned by you is useful in this problem?
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