UDF temperature profile

B.Hamada · July 12, 2014, 11:24

Quote:

Originally Posted by ghost82

Ok, but since we cannot read the future

you can only evaluate temperatures at time t and t-deltat and not deltat+t.

Again, start writing some code, someone will help you to go through your code.

Daniele

Thank you brother, i'll try

B.Hamada · July 13, 2014, 21:18

Hi Friends

I wrote this code, please can someone tell me if my UDF was correct, and if there are errors, you could fix it.
thank you

PHP Code:


			
/#include "udf.h"
DEFINE_PROFILE(heatflux_profile, t, i)    
{              
face_t f; 
real It=750;                       
real H=232000;
real Tam=300;
real Tm=298.6;
real Ul=20;
real Eta=0.16;
real m=2;
real cs=1.4;
real cl=1.8;
real Tpv;
real time;
begin_f_loop(f, thread)
 {   
    Tpv = C_T(c,t);
    time = RP_Get_Real("physical-time-step"); 
    if(Tam<Tpv<Tm) 
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam) *time+Eta*It*Time+m*cs*(Tpv-Tam);
    else if(Tpv=Tm)
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam)*time+Eta*It*Time+m*cs*(Tm-Tam)+H;
    else(Tpv>Tm)
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam)*time+Eta*It*Time+m*cs*(Tm-Tam)+H+m*cl*(Tpv-Tm);
 }
end_f_loop(f,thread)
}

When I compiled my UDF, an error occurred, but I can not fix it.
help me please
error line 16: c: undeclared variable.

I-mech · July 14, 2014, 03:05

Quote:

Originally Posted by B.Hamada

Hi Friends

I wrote this code, please can someone tell me if my UDF was correct, and if there are errors, you could fix it.
thank you

PHP Code:


			
/#include "udf.h"
DEFINE_PROFILE(heatflux_profile, t, i)    
{              
face_t f; 
real It=750;                       
real H=232000;
real Tam=300;
real Tm=298.6;
real Ul=20;
real Eta=0.16;
real m=2;
real cs=1.4;
real cl=1.8;
real Tpv;
real time;
begin_f_loop(f, thread)
 {   
    Tpv = C_T(c,t);
    time = RP_Get_Real("physical-time-step"); 
    if(Tam<Tpv<Tm) 
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam) *time+Eta*It*Time+m*cs*(Tpv-Tam);
    else if(Tpv=Tm)
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam)*time+Eta*It*Time+m*cs*(Tm-Tam)+H;
    else(Tpv>Tm)
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam)*time+Eta*It*Time+m*cs*(Tm-Tam)+H+m*cl*(Tpv-Tm);
 }
end_f_loop(f,thread)
}

When I compiled my UDF, an error occurred, but I can not fix it.
help me please
error line 16: c: undeclared variable.

you have used t in your second line DEFINE_PROFILE(heatflux_profile, t, i)
and then you have used thread in begin_f_loop(f, thread) and in end_f_loop(f,thread).
You have to decide. Use t or thread in both.

Let's try as follow, it should work. I hope

PHP Code:


			
/#include "udf.h"
DEFINE_PROFILE(heatflux_profile, t, i)    
{              
face_t f; 
real It=750;                       
real H=232000;
real Tam=300;
real Tm=298.6;
real Ul=20;
real Eta=0.16;
real m=2;
real cs=1.4;
real cl=1.8;
real Tpv;
real time;
begin_f_loop(f, t)
 {   
    Tpv = C_T(c,t);
    time = RP_Get_Real("physical-time-step"); 
    if(Tam<Tpv<Tm) 
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam) *time+Eta*It*Time+m*cs*(Tpv-Tam);
    else if(Tpv=Tm)
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam)*time+Eta*It*Time+m*cs*(Tm-Tam)+H;
    else(Tpv>Tm)
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam)*time+Eta*It*Time+m*cs*(Tm-Tam)+H+m*cl*(Tpv-Tm);
 }
end_f_loop(f,t)
}

ghost82 · July 14, 2014, 08:02

Quote:

Originally Posted by B.Hamada

Hi Friends

I wrote this code, please can someone tell me if my UDF was correct, and if there are errors, you could fix it.
thank you

PHP Code:


			
/#include "udf.h"
DEFINE_PROFILE(heatflux_profile, t, i)    
{              
face_t f; 
real It=750;                       
real H=232000;
real Tam=300;
real Tm=298.6;
real Ul=20;
real Eta=0.16;
real m=2;
real cs=1.4;
real cl=1.8;
real Tpv;
real time;
begin_f_loop(f, thread)
 {   
    Tpv = C_T(c,t);
    time = RP_Get_Real("physical-time-step"); 
    if(Tam<Tpv<Tm) 
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam) *time+Eta*It*Time+m*cs*(Tpv-Tam);
    else if(Tpv=Tm)
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam)*time+Eta*It*Time+m*cs*(Tm-Tam)+H;
    else(Tpv>Tm)
           F_PROFILE(f,t,i) = Ul*(Tpv*Tam)*time+Eta*It*Time+m*cs*(Tm-Tam)+H+m*cl*(Tpv-Tm);
 }
end_f_loop(f,thread)
}

When I compiled my UDF, an error occurred, but I can not fix it.
help me please
error line 16: c: undeclared variable.

Hi,
your equations look completely different in respect of what you posted before..
You are using c in the C_T(c,t) which is your cell temperature but you are not declaring what is c (as the description of error); you are using c (cell) inside and f (face) loop.
If you want the mean of the temperature of the pcm domain you have to first do a c loop over the pcm domain and calculate the mean temperature, then use the f loop to calculate the boundary profile.
Also this "if(Tam<Tpv<Tm)" should be "if (Tpv>Tam) && (Tpv<Tm)".
And also C langiage is case sensitive: time is different than Time, and you are not declaring what is Time.
"Tpv=Tm" assigns Tm to Tpv: it should be Tpv==Tm.

Daniele

PS: Condition Tam<Tpv<Tm will never be possible because you defined Tm<Tam!!

B.Hamada · July 14, 2014, 17:48

Hi

I changed the equation for the heat flux exerted on the pvhotovoltaique PANEL, an attached image shows the equation

B.Hamada · July 17, 2014, 16:55

HTML Code:

#include "udf.h"
DEFINE_PROFILE(heatflux_profile, t, F, i)    
{              
face_t f; 
real It=750;                       
real H=232000;
real Tam=300;
real Tm=298.6;
real Ul=20;
real Eta=0.16;
real m=2;
real cs=1.4;
real cl=1.8;
real temp;
temp = F_T(f,t);
real Time;
Time = RP_Get_Real("physical-time-step");
begin_f_loop(f, t)
 {   
    if((temp>Tam) && (temp<Tm)
           F_PROFILE(f,t,i) = Ul*(temp*Tam) *time+Eta*It*Time+m*cs*(temp-Tam);
    else if(temp==Tm)
           F_PROFILE(f,t,i) = Ul*(temp*Tam)*time+Eta*It*Time+m*cs*(Tm-Tam)+H;
    else(temp>Tm)
           F_PROFILE(f,t,i) = Ul*(temp*Tam)*time+Eta*It*Time+m*cs*(Tm-Tam)+H+m*cl*(temp-Tm);
 }
end_f_loop(f,t)
}

GM_XIII · July 18, 2014, 07:16

Do you keep getting the same error?

B.Hamada · July 18, 2014, 12:16

Quote:

Originally Posted by GM_XIII

Do you keep getting the same error?

Hi

Yes the same error.

sircorp · June 21, 2015, 03:08

Quote:

Originally Posted by flotus1

Since you refuse to be more descriptive, I have to make some assumptions

With "degrees" you mean °C, so I change the temperature variation from 298K-323K.
The x-axis coincides with the axis of the cylinder and the y-axis is from "bottom" to "top".
Thus the temperature varies linearly with the y-axis, with the highest temperature at the greatest positive y-extent of the surface.

Code:

#include "udf.h"

DEFINE_PROFILE(temp_linear, thread, position) 
{
real x[ND_ND];
face_t f;
real tmin, tmax, d;

tmin = 298.0;
tmax = 323.0;
d = 0.47;

  begin_f_loop(f, thread)
    {
      F_CENTROID(x,f,thread);
      F_PROFILE(f, thread, position) = (tmin+tmax)/2.0 + (tmax-tmin)/d*x[1];
    }
  end_f_loop(f, thread)
}

Is "d" a constant or a diameter of the pipe who surface temperature we are trying to create a profile. In case irregular geometry it is better to put d = 1( i mean avoid "d" altogether ( default d= 1))

Thanks

Shane

Ericson · June 21, 2015, 10:47

Need help!!
i got this message when i'm trying to compile my udf
can anyone solve this error message?

pakk · June 22, 2015, 04:01

Yes. Look at you code, and check lines 3, 4 and 11, something is wrong there.

Ericson · June 22, 2015, 08:57

This is my code, i don't know what is wrong here..
can you find the mistakes sir?

Ericson · June 22, 2015, 08:59

I'm trying to make code for rolling motion of ship..

pakk · June 22, 2015, 09:19

Yes I can, and I can show you how. Just read the error messages!

The first error you get says that there are not enough actual parameters in line 3.
So, go ahead, count how many parameters you have (hint: "roll" is a parameter, "dt" is a parameter, "omega" is a parameter, "time" is a parameter and "dtime" is a parameter.) Then look up in the help how many parameters there should be, and you will see something you did wrong.

Ericson · June 22, 2015, 09:57

can you fix my code please?
i can't see what i must doing in help..

pakk · June 22, 2015, 10:01

Seriously?
Ok, you are using the macro "DEFINE_CG_MOTION". Look up in the help how many parameters that needs...

Ericson · June 23, 2015, 01:00

i've trying to fixed my codes but when i'm compiling i have another error like this...

pakk · June 23, 2015, 02:44

I don't understand why you send me a private message telling that you use notepad.
Using notepad does not prevent you from opening the Fluent manual, and looking at how the macro "DEFINE_CG_MOTION" should be used.

Do you know how to open the Fluent manual?
Do you know how to search in the Fluent manual?

Ericson · June 23, 2015, 08:31

yes i can,, i have seen fluent manual and i have fixed my code..
but when i'm compiling the code again, i got error messages above..
what should i do?

pakk · June 23, 2015, 08:49

I am not paranormal, so if you don't show your code I can never know what is wrong.

July 13, 2014, 21:18		#42
B.Hamada Member Mohamed Join Date: Jan 2011 Location: Algeria Posts: 46 Rep Power: 15	Hi Friends I wrote this code, please can someone tell me if my UDF was correct, and if there are errors, you could fix it. thank you PHP Code: /#include "udf.h" DEFINE_PROFILE(heatflux_profile, t, i) { face_t f; real It=750; real H=232000; real Tam=300; real Tm=298.6; real Ul=20; real Eta=0.16; real m=2; real cs=1.4; real cl=1.8; real Tpv; real time; begin_f_loop(f, thread) { Tpv = C_T(c,t); time = RP_Get_Real("physical-time-step"); if(Tam<Tpv<Tm) F_PROFILE(f,t,i) = Ul(TpvTam) time+EtaItTime+mcs(Tpv-Tam); else if(Tpv=Tm) F_PROFILE(f,t,i) = Ul(TpvTam)time+EtaItTime+mcs(Tm-Tam)+H; else(Tpv>Tm) F_PROFILE(f,t,i) = Ul(TpvTam)time+EtaItTime+mcs(Tm-Tam)+H+mcl*(Tpv-Tm); } end_f_loop(f,thread) } When I compiled my UDF, an error occurred, but I can not fix it. help me please error line 16: c: undeclared variable.

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July 18, 2014, 07:16		#47
GM_XIII Member David Join Date: Aug 2012 Posts: 48 Rep Power: 13	Do you keep getting the same error?

June 22, 2015, 04:01		#51
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 26	Yes. Look at you code, and check lines 3, 4 and 11, something is wrong there.

June 22, 2015, 08:59		#53
Ericson New Member Ericson Join Date: Jun 2015 Posts: 10 Rep Power: 10	I'm trying to make code for rolling motion of ship..

June 22, 2015, 09:19		#54
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 26	Yes I can, and I can show you how. Just read the error messages! The first error you get says that there are not enough actual parameters in line 3. So, go ahead, count how many parameters you have (hint: "roll" is a parameter, "dt" is a parameter, "omega" is a parameter, "time" is a parameter and "dtime" is a parameter.) Then look up in the help how many parameters there should be, and you will see something you did wrong.

June 22, 2015, 09:57		#55
Ericson New Member Ericson Join Date: Jun 2015 Posts: 10 Rep Power: 10	can you fix my code please? i can't see what i must doing in help..

June 22, 2015, 10:01		#56
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 26	Seriously? Ok, you are using the macro "DEFINE_CG_MOTION". Look up in the help how many parameters that needs...

June 23, 2015, 02:44		#58
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 26	I don't understand why you send me a private message telling that you use notepad. Using notepad does not prevent you from opening the Fluent manual, and looking at how the macro "DEFINE_CG_MOTION" should be used. Do you know how to open the Fluent manual? Do you know how to search in the Fluent manual?

June 23, 2015, 08:31		#59
Ericson New Member Ericson Join Date: Jun 2015 Posts: 10 Rep Power: 10	yes i can,, i have seen fluent manual and i have fixed my code.. but when i'm compiling the code again, i got error messages above.. what should i do?

June 23, 2015, 08:49		#60
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 26	I am not paranormal, so if you don't show your code I can never know what is wrong.