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Old   May 5, 2011, 05:14
Default help temperature profil
  #1
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nhh
Join Date: May 2011
Posts: 12
Rep Power: 6
bounhh is on a distinguished road
Hello
Help
I want to introduce an array of temperature fonction of time as a boundary condition to simulate unsteady conduction problem by using udf
I try this udf
NNN time in hours
/************************************************** ********************
unsteady.c
UDF for specifying a transient temperature profile boundary condition
TT temperature

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

#include "udf.h"


DEFINE_PROFILE(unsteady_TEMP, thread, position)
{
face_t f;
float t = CURRENT_TIME;
float TT[24];
int NNN;
int first = 1;


TT[1]=31.2 + 273.;
TT[2]=30.9 + 273.;
TT[3]=30.3 + 273.;
TT[4]=30. + 273.;
TT[5]=29.6 + 273.;
TT[6]=29.2 + 273.;
TT[7]=29.8 + 273.;
TT[8]=31.3 + 273.;
TT[9]=32.9 + 273.;
TT[10]=34.7 + 273.;
TT[11]=36.1 + 273.;
TT[12]=36.9 + 273.;
TT[13]=37.6 + 273.;
TT[14]=38.2 + 273.;
TT[15]=38.2 + 273.;
TT[16]=37.9 + 273.;
TT[17]=37.7 + 273.;
TT[18]=36.7 + 273.;
TT[19]=35.3 + 273.;
TT[20]=34.6 + 273.;
TT[21]=33.9 + 273.;
TT[22]=33.3 + 273.;
TT[23]=32.6 + 273.;
TT[24]=31.9 + 273.;



begin_f_loop(f, thread)
{

t = CURRENT_TIME;
if (first == 1){
first_iteration=0;
if(t < 3600.)
{

NNN = 1;
F_PROFILE(f, thread, position) = TT[NNN];

}
else if ((t == (NNN*3600.)) && (NNN <= 23) ){
NNN++;


F_PROFILE(f, thread, position) = TT[NNN];
printf("\n NNN=%d fprofil=%f t=%f\n",NNN,F_PROFILE(f, thread, position),t);
}
}
}

end_f_loop(f, thread)
}
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Old   May 5, 2011, 05:18
Default help temperature profil
  #2
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nhh
Join Date: May 2011
Posts: 12
Rep Power: 6
bounhh is on a distinguished road
Hello
Help
I want to introduce an array of temperature fonction of time as a boundary condition to simulate unsteady conduction problem by using udf
I try this udf

/************************************************** ********************
unsteady.c
UDF for specifying a transient temperature profile boundary condition
TT temperature
NNN time in hours
************************************************** *********************/

#include "udf.h"


DEFINE_PROFILE(unsteady_TEMP, thread, position)
{
face_t f;
float t = CURRENT_TIME;
float TT[24];
int NNN;
int first = 1;


TT[1]=31.2 + 273.;
TT[2]=30.9 + 273.;
TT[3]=30.3 + 273.;
TT[4]=30. + 273.;
TT[5]=29.6 + 273.;
TT[6]=29.2 + 273.;
TT[7]=29.8 + 273.;
TT[8]=31.3 + 273.;
TT[9]=32.9 + 273.;
TT[10]=34.7 + 273.;
TT[11]=36.1 + 273.;
TT[12]=36.9 + 273.;
TT[13]=37.6 + 273.;
TT[14]=38.2 + 273.;
TT[15]=38.2 + 273.;
TT[16]=37.9 + 273.;
TT[17]=37.7 + 273.;
TT[18]=36.7 + 273.;
TT[19]=35.3 + 273.;
TT[20]=34.6 + 273.;
TT[21]=33.9 + 273.;
TT[22]=33.3 + 273.;
TT[23]=32.6 + 273.;
TT[24]=31.9 + 273.;



begin_f_loop(f, thread)
{

t = CURRENT_TIME;
if (first == 1){
first=0;
if(t < 3600.)
{

NNN = 1;
F_PROFILE(f, thread, position) = TT[NNN];

}
else if ((t == (NNN*3600.)) & (NNN <= 23) ){
NNN++;


F_PROFILE(f, thread, position) = TT[NNN];
printf("\n NNN=%d fprofil=%f t=%f\n",NNN,F_PROFILE(f, thread, position),t);
}
}
}

end_f_loop(f, thread)
}
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Old   May 5, 2011, 07:51
Default
  #3
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Jn
Join Date: Mar 2010
Location: Slovakia
Posts: 23
Rep Power: 7
argeus is on a distinguished road
Hi, try this. Not sure if it is OK.


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

float TT[24];
int NNN;
float time;

TT[1]=31.2 + 273.;
TT[2]=30.9 + 273.;
TT[3]=30.3 + 273.;
TT[4]=30. + 273.;
TT[5]=29.6 + 273.;
TT[6]=29.2 + 273.;
TT[7]=29.8 + 273.;
TT[8]=31.3 + 273.;
TT[9]=32.9 + 273.;
TT[10]=34.7 + 273.;
TT[11]=36.1 + 273.;
TT[12]=36.9 + 273.;
TT[13]=37.6 + 273.;
TT[14]=38.2 + 273.;
TT[15]=38.2 + 273.;
TT[16]=37.9 + 273.;
TT[17]=37.7 + 273.;
TT[18]=36.7 + 273.;
TT[19]=35.3 + 273.;
TT[20]=34.6 + 273.;
TT[21]=33.9 + 273.;
TT[22]=33.3 + 273.;
TT[23]=32.6 + 273.;
TT[24]=31.9 + 273.;

begin_f_loop(f, thread)
{
F_CENTROID(x, f, thread);
y = x[1];

time = CURRENT_TIME/3600;

if (time>=24.) // you need to fix it
;
else if (time >= 23.)
NNN=23;
else if (time >= 22.)
NNN=22;
//and so on
.
.
.

F_PROFILE(f, thread, position) = TT[NNN];
}
end_f_loop(f,thread)
}

another way Im not sure if it is possible is to declare variable NNN as integer and set NNN=CURRENT_TIME/3600; (and take care about NNN=0)
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Old   May 5, 2011, 11:12
Default
  #4
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nhh
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Its very good idea
Thank you very much
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