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UDF error_ undeclared variable

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Old   December 16, 2019, 12:08
Unhappy UDF error_ undeclared variable
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greece
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Hello,

i am using Fluent 19.2 and i am trying a very simple UDF that i found on Ansys Customer Portal just to get familiar with that before trying to make my own UDF.
So i copy the text and produce a .c file located at the same location with my case and dat file. The UDF text follows below:


/************************************************** ********************
UDF that models a custom law for evaporation swelling of particles
************************************************** *********************/

#include "udf.h"

DEFINE_DPM_LAW(Evapor_Swelling_Law,tp,ci)
{
real swelling_coeff = 1.1;
/* first, call standard evaporation routine to calculate
the mass and heat transfer */
VaporizationLaw(tp);

/* compute new particle diameter and density */
TP_DIAM(tp) = TP_INIT_DIAM(tp)*(1. + (swelling_coeff - 1.)*
(TP_INIT_MASS(tp)-TP_MASS(tp))/(DPM_VOLATILE_FRACTION(tp)*TP_INIT_MASS(tp)));
TP_RHO(tp) = TP_MASS(tp) / (3.14159*TP_DIAM(tp)*TP_DIAM(tp)*TP_DIAM(tp)/6);
TP_RHO(tp) = MAX(0.1, MIN(1e5, TP_RHO(tp)));
}

After trying to compile it using Fluent GUI, i receive the following error:


cpp -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/main" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/addon-wrapper" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/io" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/species" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/pbns" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/numerics" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/sphysics" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/storage" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/mphase" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/bc" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/models" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/material" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/amg" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/util" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/mesh" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/udf" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/ht" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/dx" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/turbulence" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/parallel" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/etc" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/ue" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/dpm" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/dbns" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/tgrid/src" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/PRIME/tgrid/src" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/cortex/src" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/client/src" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/multiport/src" -I. -DUDFCONFIG_H="<udfconfig-host.h>" "D:/OneDrive - central.ntua.gr/drive/projects/VEF_design&exper_CFD/new_runs/recent/grid dependence/paper/non_isothermal/swel.c"
Error: D:/OneDrive - central.ntua.gr/drive/projects/VEF_design&exper_CFD/new_runs/recent/grid dependence/paper/non_isothermal/swel.c: line 15: TP_DIAM: undeclared variable

cpp -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/main" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/addon-wrapper" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/io" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/species" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/pbns" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/numerics" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/sphysics" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/storage" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/mphase" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/bc" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/models" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/material" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/amg" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/util" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/mesh" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/udf" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/ht" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/dx" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/turbulence" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/parallel" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/etc" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/ue" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/dpm" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/dbns" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/tgrid/src" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/PRIME/tgrid/src" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/cortex/src" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/client/src" -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/multiport/src" -I. -DUDFCONFIG_H="<C:/Users/PANAGI~1/AppData/Local/Temp/udfconfig-17984-node0.h>" "C:/Users/PANAGI~1/AppData/Local/Temp/swel.c.17984.0.c"
Error: C:/Users/PANAGI~1/AppData/Local/Temp/swel.c.17984.0.c: [/U]line 15: TP_DIAM: undeclared variable

Note: The second paragraph appears about 7 times with different swel.c. number

Can someone inform me on the followings:
1. Is it an compiling or code error?
2. Should i declare TP_DIAM at the beginning of the code?
3. Other possible sources of error?

Thanks in advance.
Panos
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Old   December 17, 2019, 06:23
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seems like you've changed automatically all p to tp....

change all macros names back to P
TP_DIAM -> P_DIAM
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Old   December 17, 2019, 12:44
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Quote:
Originally Posted by AlexanderZ View Post
seems like you've changed automatically all p to tp....

change all macros names back to P
TP_DIAM -> P_DIAM
Thank you Alexander for the comment.

I did make the change you proposed. Please see below the code

/************************************************** ********************
UDF that models a custom law for evaporation swelling of particles
************************************************** *********************/

#include "udf.h"

DEFINE_DPM_LAW(Evapor_Swelling_Law,p,ci)
{
real swelling_coeff = 1.1;
/* first, call standard evaporation routine to calculate
the mass and heat transfer */
VaporizationLaw(p);

/* compute new particle diameter and density */
P_DIAM(p) = P_INIT_DIAM(p)*(1. + (swelling_coeff - 1.)*(P_INIT_MASS(p)-P_MASS(p))/(DPM_VOLATILE_FRACTION(p)*P_INIT_MASS(p)));
P_RHO(p) = P_MASS(p) / (3.14159*P_DIAM(p)*P_DIAM(p)*P_DIAM(p)/6);
P_RHO(p) = MAX(0.1, MIN(1e5,P_RHO(p)));
}

The error now is the following:
cpp -I"C:\PROGRA~1\ANSYSI~1\v192\fluent\fluent19.2.0/src/main" -
.
.
.
Error: C:/Users/PANAGI~1/AppData/Local/Temp/swelp.c.2364.11.c: line 15: TP_MATERIAL: undeclared variable

The variable that appears in line 15 for the first time is P_INIT_MASS(p)

Do you think that this might cause the error?

Thank you again!
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Old   December 17, 2019, 23:17
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Code:
#include "udf.h"

DEFINE_DPM_LAW(Evapor_Swelling_Law,p,ci)
{
real swelling_coeff = 1.1;
/* first, call standard evaporation routine to calculate
the mass and heat transfer */
VaporizationLaw(p);

/* compute new particle diameter and density */
P_DIAM(p) = P_INIT_DIAM(p)*(1. + (swelling_coeff - 1.)*(P_INIT_MASS(p)-P_MASS(p))/(DPM_VOLATILE_FRACTION(p)*P_INIT_MASS(p)));
P_RHO(p) = P_MASS(p) / (3.14159*P_DIAM(p)*P_DIAM(p)*P_DIAM(p)/6);
P_RHO(p) = MAX(0.1, MIN(1e5,P_RHO(p)));
}
this code is compiled on my machine with no errors
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Old   December 18, 2019, 04:13
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Quote:
Originally Posted by AlexanderZ View Post
Code:
#include "udf.h"

DEFINE_DPM_LAW(Evapor_Swelling_Law,p,ci)
{
real swelling_coeff = 1.1;
/* first, call standard evaporation routine to calculate
the mass and heat transfer */
VaporizationLaw(p);

/* compute new particle diameter and density */
P_DIAM(p) = P_INIT_DIAM(p)*(1. + (swelling_coeff - 1.)*(P_INIT_MASS(p)-P_MASS(p))/(DPM_VOLATILE_FRACTION(p)*P_INIT_MASS(p)));
P_RHO(p) = P_MASS(p) / (3.14159*P_DIAM(p)*P_DIAM(p)*P_DIAM(p)/6);
P_RHO(p) = MAX(0.1, MIN(1e5,P_RHO(p)));
}
this code is compiled on my machine with no errors
Hi Alexander.

Still same issue, message is line 11: P_MATERIAL: undeclared variable

But i do intepret the UDF and not compile it since i find compliling more complicated since it involved setting of VS , open Fluent from command line etc (i have not found somewhere the PC setting steps for UDFs compiling) . IS there any other setting/ requirement that needs to be done to allow Fluent perform simple UDFs intepretation, except of (1) having code without mistakes, and (2) the code to be at the same folder with cas and dat file?

Your help is appreciated!
Thanks
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Old   December 18, 2019, 13:04
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I try to use another simple UDF that is closer to what i want to do.
Please see the code below:

/************************************************** ********************
UDF that calculates a temperature dependent swelling factor
************************************************** *********************/

#include "udf.h"

DEFINE_DPM_LAW(Swelling_Factor,p,ci)
{
real swelling_coeff;
real temp = P_T(p);
swelling_coeff = temp/400.;
return swelling_coeff;
}


After trying to interpret the UDF, Fluent returns the following error:
Error: C:/Users/PANAGI~1/AppData/Local/Temp/swelcoef2.c.11368.11.c: line 12: function returning void returns double.

Any suggestion would be appreciated.

Thanks
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Old   December 19, 2019, 00:44
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interpretation leads to errors in my machine too, so I recommend you to compile code

regarding your last code:
DEFINE_DPM_LAW has type void, it means, it doesn't return any value
in example from manual (ansys fluent customization manual) they modified density according to swelling coef. they used P_RHO(p) macro
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