[mengyue1]

hi guys, i am simulating a system, the fluid involved in this system is water,water vapor and air, because of gradient of vapor mass fraction, there exists phase change.
i don't plan to use the species model available in FLUENT, in my model, i define there phases, which are water,vapor(phase-3) and air, and also, i introduce a UDS to model the diffusion of vapor in the air, the scalar is vapor mass fraction, is that right?
I define the uds for phase-3, and i think i need define vapor/air diffusivity for this uds. but now i am confused with it. in the material pannel, each material has a "UDS Diffusivity", and which one i should introduce my udf for diffusivity? when i introduce udf to vapor, there are some error tips in FLUENT:

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: ()
but when i define the same udf for other materials(air and water), there are not errors.
Can someone tell me the reason... i think my udf should define for vapor, not the other materials...

Regards!

PS:the code is:

DEFINE_DIFFUSIVITY(diffusivity, cell, third, i)
{
Thread *mix_th, *sec_th;
real diff;
real v;
mix_th = THREAD_SUPER_THREAD(third);
sec_th = THREAD_SUB_THREAD(mix_th, 1);

if ((C_VOF(cell, sec_th)==1))
diff = 0.0;

else
diff = 3.02761*pow(10.0,-5.0)*C_MU_EFF(cell, mix_th);
return diff;
}

[mengyue1]

Dose anyone help me? thanks...and where is sega?

[mengyue1]

Dose anyone help me? Thanks....

[sega]

Originally Posted by mengyue1

Dose anyone help me? thanks...and where is sega?

sega is here!
But I think I'm not use here ...

[mengyue1]

Oh, well, thanks all the same。。。

Originally Posted by sega

sega is here!
But I think I'm not use here ...

[DaddySpeleo]

I solved such problem by this way:

1. Make UDM containing the data gotten via C_VOF.
Simle cycle C_UDMI(...)=C_VOF(...)
2. Remove C_VOF(...) from DEFINE_DIFFUSIVITY
3. Use data from UDM in DEFINE_DIFFUSIVITY.

It seems to me - this error appears in some cases when macros C_VOF try to work. For example in solid area.
Best regards...

[Kanarya]

hi,
did you manage to solve the problem...I have the same problem as you.
thanks for your help in advance!

[DaddySpeleo]

I didn't try to do smth more exept described above method - this method works.
May be Fluent 15 is better?
Best regards!