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Problem with cooling of a block.

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Old   April 26, 2016, 07:16
Default Problem with cooling of a block.
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Wojtek
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Hi,

I'm trying to calculate the process of cooling of a block made of alluminium. The block is supposed to be suspended in space with some initial temperature. The geometry looks like this:
https://i.gyazo.com/78e770987f3a9e71...76562cbbdb.png
The main issues that I have are how to set boundary conditions- in some threads I read that I need to choose "coupled" option for the box, but I don't know where I need to set the initial temperature then. I also don't understand what kind of type I need to choose for the walls of the "air box". Please help.
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Old   April 26, 2016, 09:07
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The initial temperature is an initial condition, not a boundary condition. The initial temperature is specified in the initialization pane. The exact value of the initial temperature need not be correct since it is merely an initial guess, unless you are running a transient simulation.
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Old   April 26, 2016, 10:19
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Thank you very much for your reply.

I'm going to describe a problem that is actually more important. My project goal is to check how the temperature of solar module changes due to wind loads. As I am new to CFD I created the most simple model I could think of (just to get the basic rules) which you can see here:

https://i.gyazo.com/cb5c88f8ae2cd634...b1e2d6df29.png

I set the "enclosure" part to fluid and the other block was created as one part. Next in the mesher I created most basic mesh and named my selections as follows:

inlet: https://i.gyazo.com/0f40fbe9649200f4...41ea23be25.png
outlet: https://i.gyazo.com/e41a52cc2dcbc825...d30ba1867a.png
symmetry: https://i.gyazo.com/828f21f7fe52adcc...bff9a78324.png
ground (wall): https://i.gyazo.com/1d5edb6871b4287e...3c2c451853.png

Next I connected those parts: https://i.gyazo.com/73e0b57f5a5fbf73...0c256289a2.png

In solver I turned energy equation on and moved to boundary conditions which look as follows:
https://i.gyazo.com/6760894347ed266b...8578ff7191.png
I set inlet to 2m/s and temperature of 273K and wall-solid to 300K. Then I initialized the calculation and got following results:

https://i.gyazo.com/53329ad10e3ee80d...cef2c914e2.png (the wall is the inlet), so I see there is no change in the temperature of the module despite the blowing wind. What should I change?

I tried to check those videos: https://www.youtube.com/watch?v=72NpJd2LiGE
https://www.youtube.com/watch?v=4y_wcH8MpAE

But still didn't get that much of help.
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Old   April 26, 2016, 15:16
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Is this a steady or transient simulation? Did you even run any calculation?

All I see are the initial conditions. Is there even any flow?
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Old   April 26, 2016, 15:21
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It is a steady one. Yes, i ran a calculation and the results are shown in the last photo.
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Old   April 27, 2016, 01:23
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You need a coupled wall at the fluid|solid interfaces. Which surfaces are wall-13 14 and 7? There is already a coupled BC on wall-7 but what about 13 and 14?
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Old   May 2, 2016, 12:16
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Honestly, I have no idea which walls those are. When I try to highlight them while checking the mesh, there is nothing and when I try to check results for them I get an ainformation: Note: zone-surface: cannot create surface from sliding interface zone.
Creating empty surface.
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