[ashkan_1984]

Dear all
I have one problem in fluent udf.I want to write one temperature-dependent source term.I want my temperature increase up to 350K because of source term,and when it reach to 350K ,source term is stop and because of free convection the temperature come back to initial values and again this cycle continue.I write one udf but I have really problem in this,please help me.
I sent the my UDF,

#include "udf.h"
DEFINE_SOURCE(cell_source, cell, thread)
{
real source;

real temp = C_T(cell, thread);
if(temp <350.15)
{
source=20000000*(1+.02*(temp-250.15));
}
if(temp>=350.15)
{
while(temp>=250.15)
{
temp = C_T(cell, thread);
source=0;
}
}
return source;
}

[blackmask]

You should have a clear definition of the point when the source terms should be switch on, and you should tell us whether such switch is global or cell-wise.

Originally Posted by ashkan_1984

Dear all
I have one problem in fluent udf.I want to write one temperature-dependent source term.I want my temperature increase up to 350K because of source term,and when it reach to 350K ,source term is stop and because of free convection the temperature come back to initial values and again this cycle continue.I write one udf but I have really problem in this,please help me.
I sent the my UDF,

#include "udf.h"
DEFINE_SOURCE(cell_source, cell, thread)
{
real source;

real temp = C_T(cell, thread);

if(temp <350.15)
{
source=20000000*(1+.02*(temp-250.15));
}
if(temp>=350.15)
{

/* this branch results in an indefinite loop */
while(temp>=250.15) /*always true because temp >= 350.15*/
{
/* it does not change the value of temp */
temp = C_T(cell, thread);
source=0;
}

}
return source;
}

[ashkan_1984]

Thanks for your answer,
The temperature of the center of channel is important for me where the cordinate axis is (0,0,0).
I have problem in second loop,when source==0,because of free convection the cell is cooled and temperature is decrease.I want when temperature reach to initial value again repeat the cycle.