[axelosc]

Hi Everybody!!

I´m working with UDF along with the Discrete Ordinate model radiation and i need to know how to obtain the surface incident radiation by an UDF.

Currently, i know that the C_DO_IRRAD(c,t,nb) macro give me the incident radiation, but i need the incident radiation in a surface by an UDF (given in the GUI by Wall Fluxes-Surface Incident Radiation).

If any want can help me, I would really appreciate it.

Thank you very much.

[AlexanderZ]

may be

F_DO_IRRAD_SHELL(f,t,nb)

best regards

[axelosc]

Thanks for your reply, I´ll try and i´ll let you know if it works.

[axelosc]

Originally Posted by AlexanderZ

may be

F_DO_IRRAD_SHELL(f,t,nb)

best regards

I tried with the macro F_DO_IRRAD_SHELL(f,t,nb), however, I have a zero result . Here is my simple code:

#include "udf.h"

DEFINE_ON_DEMAND(F_DO)
{
Domain *d=Get_Domain(1);
int ID = 16; /*Boundary condition ID*/
Thread *t = Lookup_Thread(d,ID);
face_t f;
real temp=0;
real sum=0;

begin_f_loop(f,t) /*Loop over all faces*/

{
temp=F_DO_IRRAD_SHELL(f,t,0);
sum+=temp;
}
end_f_loop(f,t)

}

When i call the variable sum, it gives me a zero result.
Can anyone help me?

Thanks

[AlexanderZ]

How did you call variable sum?
You have nothing in your code regarding output

best regards

[axelosc]

Sorry for copy the code incomplete...

#include "udf.h"

DEFINE_ON_DEMAND(F_DO)
{
Domain *d=Get_Domain(1);
int ID = 16; /*Boundary condition ID*/
Thread *t = Lookup_Thread(d,ID);
face_t f;
real temp=0;
real sum=0;

begin_f_loop(f,t) /*Loop over all faces*/

{
temp=F_DO_IRRAD_SHELL(f,t,0);
sum+=temp;
}
end_f_loop(f,t)
printf("Suma1 temp: %f\n",sum);
}


Thanks

[sasa mohamed]

Dear axelosc,

Did u find what's the error in ur code? If u got it, please share it here. Thanks in advance

BR
sasa

[shadymody]

anyone got a solution? im trying to define incident radiation using the expression above to use it in another equation but I'm getting errors

[AlexanderZ]

Originally Posted by shadymody

anyone got a solution? im trying to define incident radiation using the expression above to use it in another equation but I'm getting errors

specify your question clear
code above should be:

#include "udf.h"

DEFINE_ON_DEMAND(F_DO)
{
Domain *d;
int ID = 16; /*Boundary condition ID*/
Thread *t = Lookup_Thread(d,ID);
face_t f;
d=Get_Domain(1)
real temp=0;
real sum=0;

begin_f_loop(f,t) /*Loop over all faces*/

{
temp=F_DO_IRRAD_SHELL(f,t,0);
sum+=temp;
}
end_f_loop(f,t)
sum = PRF_GRSUM1(sum);
Message("Suma1 temp: %f\n",sum);
}

take into account that ID = 16 is id of wall, which is different for your case, check correct ID for your case in fluent GUI

[shadymody]

Originally Posted by AlexanderZ

specify your question clear
code above should be:

#include "udf.h"

DEFINE_ON_DEMAND(F_DO)
{
Domain *d;
int ID = 16; /*Boundary condition ID*/
Thread *t = Lookup_Thread(d,ID);
face_t f;
d=Get_Domain(1)
real temp=0;
real sum=0;

begin_f_loop(f,t) /*Loop over all faces*/

{
temp=F_DO_IRRAD_SHELL(f,t,0);
sum+=temp;
}
end_f_loop(f,t)
sum = PRF_GRSUM1(sum);
Message("Suma1 temp: %f\n",sum);
}

take into account that ID = 16 is id of wall, which is different for your case, check correct ID for your case in fluent GUI

Dear,

here is what my ending of the code looks like

    
    UREF = urefData[induref];
    TACREF = tacrefData[indtacref];
    RHREF = rhrefData[indrhref];

    l1 = log((zrefu - (2 / 3) * hgrass) / (0.123 * hgrass));
    l2 = log((zrefh - (2 / 3) * hgrass) / (0.0123 * hgrass));
    ra = (l1 * l2) / (pow(k, 2) * UREF);
    lamda = 1.91846 * pow(10, 6) * pow(((TACREF + 273.15) / (TACREF + 239.24)), 2);
    delta = (4098 * 610.8 * exp((17.27 * TACREF) / (TACREF + 237.3))) / pow((TACREF + 237.3), 2);
    esat = (1.0007 + 3.46 * pow(10, -8) * patm) * 611.21 * exp(((18.678 - TACREF / 234.5) * TACREF) / (257.14 + TACREF));
    D = (1 - RHREF) * esat;
    gamma = patm * aircp * pow((0.622 * lamda), -1);

    begin_f_loop(f, thread)
    {
        F_CENTROID(x, f, thread);
        y = x[1];
        Incedent_Radiation= C_DO_IRRAD(x,f,thread);
        E = (delta * Incedent_Radiation + 1.225 * aircp * D / ra) / (delta + gamma * (1 + rs / ra));
        F_PROFILE(f, thread, position) = E;
    }
    end_f_loop(f, thread)
}

if you look at the E equation, I have Incedent_Radiation variable which I want to use the value to the walls that I am applying this UDF to.

I'm getting error BCS Incident_Radiation is not defined. Do I just plug your code above this section?

[AlexanderZ]

I'm getting error BCS Incident_Radiation is not defined.

where did you get it? why did you put part of code?

are C_DO_IRRAD(x,f,thread); and F_DO_IRRAD_SHELL(f,t,0); the same? (no)
you need

F_DO_IRRAD_SHELL(f,t,0);

inside face loop

probably "Incident_Radiation" is not defined just because you didn't define that variable in your code

[shadymody]

Originally Posted by AlexanderZ

where did you get it? why did you put part of code?

are C_DO_IRRAD(x,f,thread); and F_DO_IRRAD_SHELL(f,t,0); the same? (no)
you need

F_DO_IRRAD_SHELL(f,t,0);

inside face loop

probably "Incident_Radiation" is not defined just because you didn't define that variable in your code

Dear, sorry for the inconvenience.

I did not include the complete code because I thought that it was too long to be displayed here, sorry for that

I will include it below after following your advice, I'm not actually sure of what I did, so please tell me if this should work as intended.

I did not get any errors when interpreting this one so I hope it works as intended. i spent a lot of time on this bcs I have no background on UDFs and could not find a clear reference.

thanks in advance

#include "udf.h"

double rs=83.33;
double zrefu=30.0;
double zrefh=30.0;
double hgrass=0.1;
double patm=101325.0;
double aircp=1008.0;
double k=0.42;

float UREF;
float TACREF;
float RHREF;

int induref;
int indtacref;
int indrhref;

float urefData[24] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24};
float tacrefData[24] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24};
float rhrefData[24] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24};

DEFINE_PROFILE(PME_profile, thread, position)
{
    float x[ND_ND];
    float y;
    float E, ra, lamda, gamma, delta, D, esat, l1, l2, Incedent_Radiation;
    face_t f;

    real current_time;
    current_time = CURRENT_TIME;
    current_time /= 60;


    if (current_time < 60)
    {
        induref = 0;
        indtacref = 0;
        indrhref = 0;
    }
    else if (current_time < 120)
    {
        induref = 1;
        indtacref = 1;
        indrhref = 1;
    }
    else if (current_time < 180)
    {
        induref = 2;
        indtacref = 2;
        indrhref = 2;
    }
    else if (current_time < 240)
    {
        induref = 3;
        indtacref = 3;
        indrhref = 3;
    }
    else if (current_time < 300)
    {
        induref = 4;
        indtacref = 4;
        indrhref = 4;
    }
    else if (current_time < 360)
    {
        induref = 5;
        indtacref = 5;
        indrhref = 5;
    }
    else if (current_time < 420)
    {
        induref = 6;
        indtacref = 6;
        indrhref = 6;
    }
    else if (current_time < 480)
    {
        induref = 7;
        indtacref = 7;
        indrhref = 7;
    }
    else if (current_time < 540)
    {
        induref = 8;
        indtacref = 8;
        indrhref = 8;
    }
    else if (current_time < 600)
    {
        induref = 9;
        indtacref = 9;
        indrhref = 9;
    }
    else if (current_time < 660)
    {
        induref = 10;
        indtacref = 10;
        indrhref = 10;
    }
    else if (current_time < 720)
    {
        induref = 11;
        indtacref = 11;
        indrhref = 11;
    }
    else if (current_time < 780)
    {
        induref = 12;
        indtacref = 12;
        indrhref = 12;
    }
    else if (current_time < 840)
    {
        induref = 13;
        indtacref = 13;
        indrhref = 13;
    }
    else if (current_time < 900)
    {
        induref = 14;
        indtacref = 14;
        indrhref = 14;
    }
    else if (current_time < 960)
    {
        induref = 15;
        indtacref = 15;
        indrhref = 15;
    }
    else if (current_time < 1020)
    {
        induref = 16;
        indtacref = 16;
        indrhref = 16;
    }
    else if (current_time < 1080)
    {
        induref = 17;
        indtacref = 17;
        indrhref = 17;
    }
    else if (current_time < 1140)
    {
        induref = 18;
        indtacref = 18;
        indrhref = 18;
    }
    else if (current_time < 1200)
    {
        induref = 19;
        indtacref = 19;
        indrhref = 19;
    }
    else if (current_time < 1260)
    {
        induref = 20;
        indtacref = 20;
        indrhref = 20;
    }
    else if (current_time < 1320)
    {
        induref = 21;
        indtacref = 21;
        indrhref = 21;
    }
    else if (current_time < 1380)
    {
        induref = 22;
        indtacref = 22;
        indrhref = 22;
    }
    else
    {
        induref = 23;
        indtacref = 23;
        indrhref = 23;
    }

    UREF = urefData[induref];
    TACREF = tacrefData[indtacref];
    RHREF = rhrefData[indrhref];

    l1 = log((zrefu - (2 / 3) * hgrass) / (0.123 * hgrass));
    l2 = log((zrefh - (2 / 3) * hgrass) / (0.0123 * hgrass));
    ra = (l1 * l2) / (pow(k, 2) * UREF);
    lamda = 1.91846 * pow(10, 6) * pow(((TACREF + 273.15) / (TACREF + 239.24)), 2);
    delta = (4098 * 610.8 * exp((17.27 * TACREF) / (TACREF + 237.3))) / pow((TACREF + 237.3), 2);
    esat = (1.0007 + 3.46 * pow(10, -8) * patm) * 611.21 * exp(((18.678 - TACREF / 234.5) * TACREF) / (257.14 + TACREF));
    D = (1 - RHREF) * esat;
    gamma = patm * aircp * pow((0.622 * lamda), -1);

    begin_f_loop(f, thread)
    {
        F_CENTROID(x, f, thread);
        y = x[1];
        Incedent_Radiation= F_DO_IRRAD_SHELL(f,thread,0);
        E = (delta * Incedent_Radiation + 1.225 * aircp * D / ra) / (delta + gamma * (1 + rs / ra));
        F_PROFILE(f, thread, position) = E;
    }
    end_f_loop(f, thread)
}

[AlexanderZ]

the code you've showed last is correct.
what errors do you have?

[shadymody]

Originally Posted by AlexanderZ

the code you've showed last is correct.
what errors do you have?

I did not get any errors. I was just asking if its "technically" correct.