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-   -   Who can fix the error on this UDF code??? (https://www.cfd-online.com/Forums/fluent-udf/187523-who-can-fix-error-udf-code.html)

NPs May 9, 2017 03:40

Who can fix the error on this UDF code???
 
1 Attachment(s)
Hi everyone, I have to implement a UDF in fluent as a Wall Heat Generation Rate Profile on this geometric model
Attachment 55881

The wall heat generation must be in the wall of the inner cylinder
and it's defined by these 2 equations


T = (((mu_0)*3,14*(chi_2)*(frequency)*(magnetic_field_ quadrato))/(((mass_NPs)*(cp_NPs))+(cp_water)*(mass_water)))*t ;
real source = ((mass_NPs)*(cp_NPs))+(cp_water)*(mass_water))* T;
I got T then i got real source,the others are parameters with numeric values.
I wrote this code for the UDF

#include "udf.h"
#define mu_0 1,256637*10^(-6) // permeabilitą elettrica vuoto (H/m)//
#define chi_2 1,25 //suscettivitą magnetica
#define frequency 344000 //frequenza campo
#define magnetic_field_quadrato 21000 //campo magnetico
#define mass_NPs 1.5 //massa nanoparticelle
#define cp_NPs 0.67 //calore specifico nanoparticelle
#define mass_water 498.5 //massa acqua
#define cp_water 4.18 //calore specifico acqua


DEFINE_PROFILE(wallheatgenerate,thread,i)
{
real t = CURRENT_TIME
delta_T = (((mu_0)*3,14*(chi_2)*(frequency)*(magnetic_field_ quadrato))/(((mass_NPs)*(cp_NPs))+(cp_water)*(mass_water)))*t ;
real source = ((mass_NPs)*(cp_NPs))+(cp_water)*(mass_water))* T;;
face_t f;

begin_f_loop(f,thread)
F_PROFILE(f,thread,i) = source;
end_f_loop(f,thread)
}

Then i got this error "f:undeclared variable" and "parse error" on these lines

15 delta_T = (((mu_0)*3,14*(chi_2)*(frequency)*(magnetic_field_ quadrato))/(((mass_NPs)*(cp_NPs))+(cp_water)*(mass_water)))*t ;

16 real source = ((mass_NPs)*(cp_NPs))+(cp_water)*(mass_water))* T;;

17 face_t f;

Anyone can help me to fix it?

Thanks a lot

pakk May 12, 2017 07:43

Don't use comma's inside numbers, but points.

Wrong: #define mu_0 1,256637*10^(-6)

Correct: #define mu_0 1.256637*10^(-6)

I think you did this three times in your code.

And you used two semicolons (";;") in line 16, that is not needed.

pakk May 12, 2017 07:53

Furthermore: you calculate "delta_T" but never use it. And you use "T" but never calculate it. I think you mixed the names.

KaLium June 2, 2017 06:53

"real t = CURRENT_TIME" needs semicolon

"
15 delta_T = (((mu_0)*3,14*(chi_2)*(frequency)*(magnetic_field_ quadrato))/(((mass_NPs)*(cp_NPs))+(cp_water)*(mass_water)))*t ;"

It should be "3.14", not "3,14". Use point "." for desimals

KaLium June 2, 2017 06:58

16 real source = ((mass_NPs)*(cp_NPs))+(cp_water)*(mass_water))* T;;

has two semicolons ( ;; ) and wrong amount of brakets "("


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