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derivative definition of velocity IN CFX

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Old   April 21, 2016, 05:30
Default derivative definition of velocity IN CFX
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Hi,

How do i can define velocity derivative as follow:



Thanks.

Best.

Aja
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Old   April 21, 2016, 06:44
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u.grad_x and so on for uvw and xyz.

Look in the CFX reference manual for the full list of variables, functions and operators on variables (like the gradient function).
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Old   April 21, 2016, 09:41
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Quote:
Originally Posted by ghorrocks View Post
u.grad_x and so on for uvw and xyz.

Look in the CFX reference manual for the full list of variables, functions and operators on variables (like the gradient function).
Thanks,

Should I define in Expressions? or user functions?

I want to obtain a contour by using above function in post 1.
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Old   April 21, 2016, 10:25
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I created as follows:



Now, How can i call this formula in contour panel? I want to obtain a contour by using defined function. Rotary is whole computational domain.

Method is single reference frame. in Fact, i rotate whole computational domain.

What is "Value=0.00490041"?

Last edited by aja1345; April 22, 2016 at 15:55.
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Old   April 21, 2016, 10:38
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I was wrong.

I created a new variable in expression panel as follows:




And then volume integral :



It is ok, but now How do i obtain a contour by using variable RRR? There is variable RRR in contour panel:


Last edited by aja1345; April 22, 2016 at 08:48.
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Old   April 21, 2016, 12:25
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For contours, you can only plot variables, not expressions. You must create a new variable. And then maker the definition of that variable your expression.
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Old   April 21, 2016, 15:57
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Quote:
Originally Posted by evcelica View Post
For contours, you can only plot variables, not expressions. You must create a new variable. And then maker the definition of that variable your expression.
Thanks.

According the following picture, i created new variable(VVV). Right?




But, the contour of new variable(VVV) is not very good and clear, there are not different colors in the following contour of this new variable. why?






Thanks

Last edited by aja1345; April 22, 2016 at 05:12.
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Old   April 22, 2016, 02:27
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Quote:
Originally Posted by aja1345 View Post
But, the contour of new variable(VVV) is not very good and clear, there are different colors in the following contour of this new variable. why?
Isn't that the goal of contour plots? Getting different colors according to the range of your variable? 1000 colors of contours is a bit much, maybe start with 50 or so

you probably need to adjust your color range. 'local' is a good first shot but a lot of times you still too coarse. You probably know in which range your values should be - so start with that range. Something like min= 0 , max=10. Or min=10, max= 100. Etc.
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Old   April 22, 2016, 02:32
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Quote:
Originally Posted by aja1345 View Post
What is "Value=0.00490041"?
In this case you already 'applied' your equation to a specific surface and that's why you got a result (=value). CFX solved that volume integral of your equation on surface ROTARY
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Old   April 22, 2016, 06:21
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Thanks.


Now I want to export this contour to tecplot format. there was tecplot format in Fluent(for exporting), but i dont see this format in CFX. I am grateful that guide me about this case.
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