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flow in an assembled block

Posted 24 giu 2011, 15:13 GMT-4 Fluid & Heat, Computational Fluid Dynamics (CFD) Version 4.2 2 Replies

Pooyan Tirandazi
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Hi,

I want to model a fluid duct flow in two adjacent blocks (assembled) of equal dimensions.
Basically, I should be getting the same results between the two ducts assembled together and a single duct flow.
Somebody tried this in 3d a while ago (www.comsol.com/community/forums/general/thread/9329/), but I would like to do this in 2d.

As can be seen in the attached file, the results seem to be fine.
The problem is I can only see the flow results for the bottom half of the duct.
How can I see the flow results for the top half of the duct as well?

Any help would be appreciated.

TJ
2 Replies Last Post 27 giu 2011, 08:43 GMT-4
Ruud Borger COMSOL Employee

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Posted: 1 decade ago 25 giu 2011, 05:40 GMT-4
Dear Tae Jin,

Thank you for including the model file! In this case, your two quantities of interest are called:

spf.U - flow in the bottom domain
spf2.U - flow in the top domain

What you want is a single variable that includes both of them. This can implemented in the following way:
Go to Model 1 => Definitions, and add "Variables". Select the variables to be valid in Domain 1. Give the variable some name, I choose "Velo", and set it equal to spf.U. Now make a second set of Variables, and assign them to be valid in Domain 2. Again, make "Velo" and here set it equal to spf2.U.

You are almost done now, you only need to update the solution by right-cliking Study 1=> Update solution.

Now, make a Surface plot of "Velo". Nice!

I attached the model file demonstrating this.

Best regards,

Ruud Börger,
COMSOL BV

p.s. In general, I would recommend using "Form union" instead of "Form assembly"... but in this case, don't change a winning team.

Dear Tae Jin, Thank you for including the model file! In this case, your two quantities of interest are called: spf.U - flow in the bottom domain spf2.U - flow in the top domain What you want is a single variable that includes both of them. This can implemented in the following way: Go to Model 1 => Definitions, and add "Variables". Select the variables to be valid in Domain 1. Give the variable some name, I choose "Velo", and set it equal to spf.U. Now make a second set of Variables, and assign them to be valid in Domain 2. Again, make "Velo" and here set it equal to spf2.U. You are almost done now, you only need to update the solution by right-cliking Study 1=> Update solution. Now, make a Surface plot of "Velo". Nice! I attached the model file demonstrating this. Best regards, Ruud Börger, COMSOL BV p.s. In general, I would recommend using "Form union" instead of "Form assembly"... but in this case, don't change a winning team.
Pooyan Tirandazi
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Posted: 1 decade ago 27 giu 2011, 08:43 GMT-4
Hello Ruud,

I thought I was missing something, but didn't think that the two velocities needed the same expression.

Thanks for the help!

TJ
Hello Ruud, I thought I was missing something, but didn't think that the two velocities needed the same expression. Thanks for the help! TJ

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