[lehoanganh07]

Hi,
I made simple code to calculate liquid density as Tammannn equation:
(p+pc)=k*rho*(t+t0)

this is the code:
#include "udf.h"
#define pc 1944610000
#define t0 3836.94
#define ck 472.26
DEFINE_PROPERTY(liq_rho,c,t)
{
real temp=C_T(c,t);
real p =C_P(c,t);
real rhol;
rhol=(p+pc)/ck/(temp+t0);
return rhol;
}

When I interpret and loaded the UDF file above in the density option, but the file was not loaded as in the picture below. And I got this warning

cpp -I"C:\PROGRA~1\ANSYSI~1\v140\fluent\fluent14.0.0/src" -I"C:\PROGRA~1\ANSYSI~1\v140\fluent\fluent14.0.0/cortex/src" -I"C:\PROGRA~1\ANSYSI~1\v140\fluent\fluent14.0.0/client/src" -I"C:\PROGRA~1\ANSYSI~1\v140\fluent\fluent14.0.0/multiport/src" -I. -DUDF
ONFIG_H="<udfconfig.h>" "C:\Users\Ledinhanh07\Desktop\liquid_density.c "
temp definition shadows previous definition
.entry
liq_rho:
.local.int c (r0)
.local.pointer t (r1)
0 .local.end
0 save
.local.double temp (r3)
1 ld.pointer t (r1)
3 push.int 328
5 pointer.incr
6 push.int 1688
8 pointer.incr
9 slda.pointer
10 ld.int c (r0)
12 push.int 8
14 mul.int
15 pointer.incr
16 slda.double
.local.double p (r4)
17 ld.pointer t (r1)
19 push.int 328
21 pointer.incr
22 push.int 0
24 pointer.incr
25 slda.pointer
26 ld.int c (r0)
28 push.int 8
30 mul.int
31 pointer.incr
32 slda.double
.local.double rhol (r5)
33 push.double 0
35 ld.double p (r4)
37 push.double 1.94461e+09
39 add.double
40 push.double 472.26
42 div.double
43 ld.double temp (r3)
45 push.double 3836.94
47 add.double
48 div.double
49 sto.double rhol (r5)
51 pop.double
52 ld.double rhol (r5)
54 ret.double
55 restore
56 ret.v

Error:
FLUENT received fatal signal (ACCESS_VIOLATION)
1. Note exact events leading to error.
2. Save case/data under new name.
3. Exit program and restart to continue.
4. Report error to your distributor.
Error Object: #f

The pictures as in order: 1. interpret UDF
2. load the UDF in the density panel
3. the UDF name: liq_rho is loaded
4. but when I check again, the file liq_rho dissapare

Anyone can help me?

[blackmask]

See whether this code works

#include "udf.h"
#define pc 1944610000
#define t0 3836.94
#define ck 472.26
DEFINE_PROPERTY(liq_rho,c,t)
{
    if (NULLP(THREAD_STORAGE(t, SV_P)) || NULLP(THREAD_STORAGE(t, SV_T)))
        return 1073; /* fault-safe value for rho */
    return ( C_P(c,t)+pc )/( C_T(c,t)+t0 )/ck;
}

[lehoanganh07]

Thank blackmask,

I try your code, but still got the trouble. I dont know why I could not load the UDF for water density.

[walied123]

hello every body...........need for help
i try to make an UDF for changing density as a function of coordinates(say z coordinate) but it didnot work in fluent.
this is my UDF.
#include "udf.h"
DEFINE_PROPERTY(ANODE_DENSITY, thread, position)
{
float x[ND_ND]; /* this will hold the position vector */
float t,air,anode,electrolyte,po,va,ve,n,z,a,r,l,p,d,w,y ,u,POROSITY;
cell_t c;
t= 0.00008; /* ANODE THICKNESS */
air=1.28;
anode=4500.;
electrolyte=6010.;
n=2;
z=5;
w=(n+z)/n;
y=n/(n+z);
r=pow(w,n);
l=pow(y,z);
a=r/(1-l);
begin_c_loop(c,thread)
{
C_CENTROID(x, c, thread);
va=x[3]/t;
ve=1-va;
u=x[3]/t;
p= pow(u,n);
d= pow(u,z);
POROSITY = (a*p*(1-d));
po= ((va*anode)+(ve*electrolyte));
C_R(c, thread, position) =po*(1-POROSITY)+air*POROSITY;
}
end_c_loop(c, thread)
}