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-   -   Initialisation Temperatures (http://www.cfd-online.com/Forums/cfx/89008-initialisation-temperatures.html)

harsh.bansal June 1, 2011 09:00

Initialisation Temperatures
 
1 Attachment(s)
Hi,

The geometry for my problem is :
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These are concentric cylinders with the solid(thick) part denoted by '=' sign.
i.e. There are two diameters for inner-cylinder (solid part in between) and one outer diameter.
I have just started using CFX

I am finding some initialisation temperatures as troublesome like :
In the Solid Domain initialisation its asking for some temperature value after choosing the option as Automatic with value.

Also, in the Fluid Domain, if i am giving the boundary type as opening for inner-fluid outlet as well as for outer fluid outlet, it asks for an opening temperature.

I just wanted to know what these temperatures mean and what values should they be assigned ?

I am attaching a .txt file providing the various conditions that i have given.

If anyone knows it then please do reply.
Thanks...

baserinia June 1, 2011 11:42

Hi,
Please read the documentation first. The answers are explained there.
1) Automatic with value means you must supply a value. If you don't want to do so, just choose automatic.
2) An opening boundary condition is for cases that you're not sure about the flow direction. For an outlet, use outlet boundary condition.

harsh.bansal June 2, 2011 01:07

Hello baserinia,
Thank you for your reply.

For the Solid domain initialisation temperature, I wanted to know what the Automatic with value means.

Means what that value of temperature signifies (Its physical significance).

I know that it wouldn't ask me for a temperature value if I have given it as Automatic.

Thanks...

baserinia June 2, 2011 13:18

Quote:

Originally Posted by harsh.bansal (Post 310225)
Means what that value of temperature signifies (Its physical significance).

The value is your initial guess for the temperature field. If you can come up with a good guess, the solution converges faster and more robustly.

harsh.bansal June 3, 2011 01:50

Thank you baserinia

Can you tell me when we give the Solid domain initialisation temperature as Automatic, then is there any place where we can see what value has been given assigned to that temperature ...

baserinia June 3, 2011 12:14

The automatic temperature would be an area weighted average of boundary temperatures. You can turn of the energy equation, set the maximum iterations to 1 and look at the temperature distribution in the Post.


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