[Ionut G]

Hi all,

I want to extract the dynamic viscosity for each cell in an udf DEFINE_WALL_FUNCTIONS.
Is C_MU_L(c,t) the dynamic viscosity? If not, how can I extract it from fluent?

Here is the code I use:


#include "udf.h"
#include "mem.h"

#define CMU 0.09
#define KARMAN 0.4187
#define E 9.793
#define MU 1.1e-3

DEFINE_WALL_FUNCTIONS(std_wf, f, t, c0, t0, wf_ret, yPlus, Emod)
{
real k, dist, y_plus;
real wf_value;

begin_c_loop(c0, t0)
{
rho = C_R(c0,t0);
mu = C_MU_L(c0,t0);

k = C_K(c0,t0);
dist = (yPlus*MU)/(DENSITY*pow(CMU,0.25)*pow(k,0.5));
y_plus = (DENSITY*pow(CMU,(1./4.))*pow(k,(1./2.))*dist)/MU;
}
end_c_loop(c0, t0)

switch (wf_ret)
{
case UPLUS_LAM:
wf_value = y_plus;
break;
case UPLUS_TRB:
wf_value = log(E*y_plus)/KARMAN;
break;
case DUPLUS_LAM:
wf_value = 1.0;
break;
case DUPLUS_TRB:
wf_value = 1./(KARMAN*y_plus);
break;
case D2UPLUS_TRB:
wf_value = -1./(KARMAN*y_plus*y_plus);
break;
default:
printf("Wall function return value unavailable\n");
}
return wf_value;
}

Any help will be appreciated, thank you!

[KevinZ09]

Yes, C_MU_L(c,t) is the dynamic viscosity macro.

[Ionut G]

Hi Kevin, thank you very much!

[Ionut G]

Hi,

I want to write in a variable the distance from the wall to the first cell using C_UDMI but i receive the following error:

iter continuity x-velocity y-velocity z-velocity k epsilon time/iter

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Node 0: Process 88256: Received signal SIGSEGV.

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Node 1: Process 87820: Received signal SIGSEGV.

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Node 2: Process 88216: Received signal SIGSEGV.

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Node 3: Process 88212: Received signal SIGSEGV.

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Node 4: Process 88284: Received signal SIGSEGV.

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Node 5: Process 88236: Received signal SIGSEGV.

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Node 6: Process 87872: Received signal SIGSEGV.

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Node 7: Process 87804: Received signal SIGSEGV.

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Node 8: Process 88268: Received signal SIGSEGV.

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Node 9: Process 87880: Received signal SIGSEGV.

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Node 10: Process 88280: Received signal SIGSEGV.

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Node 11: Process 87812: Received signal SIGSEGV.

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Node 12: Process 88248: Received signal SIGSEGV.

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Node 13: Process 88264: Received signal SIGSEGV.

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Node 14: Process 88004: Received signal SIGSEGV.

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Node 15: Process 86712: Received signal SIGSEGV.

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MPI Application rank 0 exited before MPI_Finalize() with status 2
The fl process could not be started.

What I did wrong?
In the Number of User-Defined Memory Locations, I set 1.
The code is compiled using MS Visual Studio, I do not get errors when I compile the code.
I attached the C code.

Thanks in advance for help.