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Old   January 16, 2007, 18:34
Default accessing far field velocity
  #1
Avinash
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Hi,

I am working on UDF for turbulent flow over a float plate.

For my calculation I need to accesses value of the velocity at the outermost cell(By outermost, I mean y=ymax).

Is there any MACRO for doing this?

Regard Avinash
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Old   January 17, 2007, 12:20
Default Re: accessing far field velocity
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suijth
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Hi Avinash,

I dont think any direct macro is available to get the macro of outermost cell. You can loop over all the cells and get the cell for which y = y_max and get its velocity.

This cell will be lying adjacent to a boundary..so you can loop over all the faces on this boundary, get the cell and cell thread adjacent to the face, get y_max cell and find velocity. standard macros are available for the above operations.

Btw could you tell me what is the application?

best wishes Sujith

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Old   January 17, 2007, 19:52
Default Re: accessing far field velocity
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Avinash
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Thanks sujith,

I am adopting a new turbulence model for analysing a flow over a GAS turbine blade. This model is based on SST k-omega model coupled with an inttermettency factor. A convection diffusion equation has been proposed for the intermittency factor. For evaluating the diffusion co-effecient of this equation, I need to know the farfield velocity corresponing to each cell. This was where the problem began to start.

hope I have described the problem proficiently

thanks again

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Old   January 18, 2007, 11:30
Default Re: accessing far field velocity
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Sujith
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thank you for the insight----and i hope the above method will work

---sujith
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Old   January 18, 2007, 14:04
Default Re: accessing far field velocity
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Avinash
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Hi,

I asked my professor abt this,

He told me, what I need to find is not free sream velocity, instead local free stream velocity. That can be found by using some sort of pressure distribution variation relation.... Thanks for the help

regards Avinash

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