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Heat flux dependence with position on a face

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Old   July 12, 2004, 17:52
Default Heat flux dependence with position on a face
  #1
Pavel
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Hi everybody !!!

I would like to have any advice about this problem...

It's related to a continuous casting problem, so i need to assign a heat flux that depends on the y coordinate ( withdrawall direction) in the 4 walls of a mould. I'm not experienced in UDF's and I'd appreciate any help about the topic.

Thanx in advance
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Old   July 13, 2004, 06:34
Default Re: Heat flux dependence with position on a face
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Andrew Garrard
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This is a realtivly simple situation to simulate using UDF's. Have a bit of a read of the Fluent 6 UDF manual to get an idea of how UDF's work. You will then need a DEFINE_PROFILE macro to define the heat flux on a face, an F_CENTROID(x, c, t) macro to get the co-ordinate value of the face centre, then and F_PROFILE macro to assign the heat flux to face in question. Have a go and if you get stuck, post again and I will do my best to help you out.
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Old   July 16, 2004, 16:10
Default Re: Heat flux dependence with position on a face
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Pavel
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Thanx andrew....

I've tried to apply the UDF as you mentioned, I can interpret it,and is available in the boundary conditions panel too, but the problem is that it does not work like it should be....

The UDF code is the next....

/************************************************** *********************

vprofile.c

UDF for specifying unsteady-state flux profile in a boundary condition ************************************************** **********************/ #include "udf.h"

DEFINE_PROFILE(flux, thread, position) { real x[ND_ND]; real y; face_t f; begin_f_loop(f, thread)

{

F_CENTROID(x,f,thread);

y = x[1];

F_PROFILE(f, thread, position) = (2680000-(2580000*(sqrt(fabs(y-0.1)))))*(-1);

} end_f_loop(f, thread) }

The equation for the Flux must be : -q = 2680000 - (2580000 x sqrt(y - 0.1 ))

as you see is in function of y......

I don't know which is the problem...but i think it has to do with the equation or maybe the function is only for use in a 2D steady problem ...but my case is an unsteady 3D problem.

Thanx a lot for your help Andrew !!! =)
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