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[Sponsors] |
March 22, 2005, 07:48 |
Simple question
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#1 |
Guest
Posts: n/a
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Hello.
Is it possible to define an expression or AV equal to Pressure.Gradient (or Velocity.Gradient) in CFX pre and use it for some calculations?? Thomas |
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March 23, 2005, 07:03 |
Re: Simple question
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#2 |
Guest
Posts: n/a
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To add some precision, I would like to get: d2u/dx2 (second derivative of Velocity u). With USER_GETVAR, I can get without problem du/dx, as I get from this routine Velocity u.Gradient and all the composant (du/dx, du/dy, du/dz). As these composant are only available in CFX-Post, I cannot use them to calculate d2u/dx2. I can just calculate Velocity u.Gradient.Gradient... which is not the same!
Someone can help me?? Thomas |
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March 24, 2005, 12:58 |
Re: Simple question
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#3 |
Guest
Posts: n/a
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Nobody able to calculate d2u/dx2??
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March 28, 2005, 13:19 |
Re: Simple question
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#4 |
Guest
Posts: n/a
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You cannot directly use gradients in CEL expressions; you'll have to write your own User Fortran routine to calculate the second derivative.
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March 28, 2005, 13:41 |
Re: Simple question
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#5 |
Guest
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Yes but how?? Because I can get the second derivative, but not d2u/dx2...
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March 29, 2005, 20:26 |
Re: Simple question
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#6 |
Guest
Posts: n/a
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Thomas, as Phil says you will have to implement a second derivative calculation in user fortran to get what you want. This is not available "built in".
Neale |
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