Hello Ansys Innovation Forum,<\/p>\n
I am encountering an error while trying to compile or interpret a User-Defined Function (UDF) in Ansys Fluent. I would like to understand the reason behind this error and find a solution to resolve it. The error message I receive is as follows:<\/p>\n
“Error: C:\/Users\/271557I\/AppData\/Local\/Temp\/evapoartion_UDF.c.24848.3.c: line 22: structure reference not implemented”<\/p>\n
To provide more context, I am including the full code of the UDF which obtained from (\/forum\/forums\/topic\/saturation-temperature-udf\/) below:<\/p>\n
#include “udf.h”<\/p>\n
#define MOLAR_MASS_WATER 18.01534 \/\/ g\/mol
#define MOLAR_MASS_AIR 28.97 \/\/ g\/mol
#define RHO_WV 0.5542 \/\/ kg\/m3
#define RHO_AIR 1.225 \/\/ kg\/m3
DEFINE_PROPERTY(saturation_temp, c, t) \/\/ t: mixture thread, c: cell variable, Cell volume
{
real vol = C_VOLUME(c, t);
Thread *pt = THREAD_SUB_THREAD(t, 0); \/\/ Primary phase thread
Thread *st = THREAD_SUB_THREAD(t, 1); \/\/ Secondary phase thread
real vf_s = C_VOF(c, st); \/\/ Get the volume fraction of secondary phases
real vf_p = 1 – vf_s; \/\/ Get the volume fraction of primary phases
real p_mix = C_P(c, t); \/\/ Get the pressure of the mixture
real p_op = RP_Get_Real(“operating-pressure”); \/\/ Get the operating pressure
real rho_p = C_R(c, pt); \/\/ Primary phase density<\/p>\n
\/\/ Get mass fractions in primary phase
real mf[2]; \/\/ to store mass fractions
Material *m = THREAD_MATERIAL(pt);
Material *sp = NULL;
int i; \/\/ Species index – 0 for water vapor and 1 for air
mixture_species_loop(m, sp, i)
{
mf[i] = C_YI(c, pt, i);
}
real p_w; \/\/ Water vapor pressure for the cell
if (vf_s == 1) \/\/ If secondary phase only
{
p_w = p_mix + p_op;
}
else \/\/ If primary phase or mixture of phases
{
\/\/ Find the partial pressure of water vapour, partial pressure = cell pressure * water mole fraction
real m_prim = rho_p * vol * vf_p; \/\/ mass of primary phase in cell
real m_wv = mf[0] * m_prim; \/\/ mass of water vapour in cell
real m_air = m_prim – m_wv; \/\/ mass of air in cell
real N_wv = m_wv \/ MOLAR_MASS_WATER; \/\/ No of moles in water vapour
real N_air = m_air \/ MOLAR_MASS_AIR; \/\/ No of moles in air
real N_total = N_wv + N_air; \/\/ total moles
p_w = (C_P(c, t)+ p_op)* (N_wv \/ N_total); \/\/ water vapour partial pressure
}
real t_sat;
t_sat = (1730.63 \/ (10.196 – log10(p_w))) + 39.724; \/\/ Calculate saturation temperature
return t_sat;
}<\/p>\n
<\/p>\n
Additionally, during the compilation process, the following error was obtained:<\/p>\n
<\/p>\n
Copyright 1987-2023 ANSYS, Inc. All Rights Reserved.
Compiler and linker: Clang (builtin)
Compiler path: “C:\\PROGRA~1\\ANSYSI~1\\v231\\fluent”\\ntbin\\clang\\bin\\clang-cl
Linker path: “C:\\PROGRA~1\\ANSYSI~1\\v231\\fluent”\\ntbin\\clang\\bin\\lld-link
C sources: [‘evapoartion_UDF.c’]
udf_names.c(6,46): error: expected ‘;’ after top level declarator
extern DEFINE_PROPERTY(saturation_temp, c, t) \/\/ t: mixture thread, c: cell variable, Cell volume;
^
;
1 error generated.
scons: *** [udf_names.obj] Error 1<\/p>\n
Done.<\/p>\n
<\/p>\n
I would appreciate any insights or suggestions regarding the reasons for these errors and how to resolve them. Thank you in advance for your valuable assistance.<\/p>\n
<\/p>\n","protected":false},"template":"","class_list":["post-291035","topic","type-topic","status-closed","hentry","topic-tag-condensation-evaporation-1","topic-tag-udf"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t