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How to use UDF about adjacent cell ?

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Old   January 31, 2018, 04:02
Post How to use UDF about adjacent cell ?
  #1
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JuBong
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Hi everyone,

To give the temperature because it can not give heat flux conditions to the inlet.

I want to change the heat flux condition to the temperature equation.

For example, When T2 is the temperature of the side cell in the flow direction, try to give T1 = T2 - dx / k * q ''.

for example,
In a square module with one cell of 0.001 m2, if the temperature T1 at the inlet is a function of T2 (the temperature of the next cell in the direction of flow), how to use UDF code to express T1 (y) = T2 (y) + 100 ?


example

#include "udf.h"
DEFINE_PROFILE(temperature, thread, position)
{
real x[ND_ND];
real y;
face_t f;
C_T(c,t);

begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
y = x[1];
F_PROFILE(f, thread, position) = C_T(c,t) + 100;
}
end_f_loop(f, thread)
}


Could you give me some advice on how to change the code?
Or is there another way of giving heat?
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Old   January 31, 2018, 20:12
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BigZ
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Quote:
Originally Posted by JuBong View Post
Hi everyone,

To give the temperature because it can not give heat flux conditions to the inlet.

I want to change the heat flux condition to the temperature equation.

For example, When T2 is the temperature of the side cell in the flow direction, try to give T1 = T2 - dx / k * q ''.

for example,
In a square module with one cell of 0.001 m2, if the temperature T1 at the inlet is a function of T2 (the temperature of the next cell in the direction of flow), how to use UDF code to express T1 (y) = T2 (y) + 100 ?


example

#include "udf.h"
DEFINE_PROFILE(temperature, thread, position)
{
real x[ND_ND];
real y;
face_t f;
C_T(c,t);

begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
y = x[1];
F_PROFILE(f, thread, position) = C_T(c,t) + 100;
}
end_f_loop(f, thread)
}


Could you give me some advice on how to change the code?
Or is there another way of giving heat?
Hi, JuBong. Maybe you can use c0 = F_C0(f, t) and t0=THREAD_T0(t) to get the adjacent cell pointer and retrieve the value you want.
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Old   February 2, 2018, 03:16
Post Thank you bigfish_1023
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JuBong
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Hello bigfish_1023

Thank you very much for your reply.

I tried using the information you gave me. ( c0=F_C0(f,t) )

The temperature of the inlet was 30K higher than the temperature of the adjacent cell.
However, the fluent does not work and the program is turned off.
Can I see what's wrong with my code?
Can you fix it?
Thank you very much for your reply.

This is my code.

------------------------------------------------
#include "udf.h"

DEFINE_PROFILE(temperature, thread, position)
{
real x[ND_ND];
real y;
Thread *t;
face_t f;
cell_t c,c0;
c0=F_C0(f,t);

begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
y = x[1];
F_PROFILE(f, thread, position) = c0+30;
}
end_f_loop(f, thread)
}
-----------------------------------------------------
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