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Help on accessing volume fraction in mixture model |
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April 20, 2009, 15:14 |
Help on accessing volume fraction in mixture model
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#1 |
New Member
Aditya Chunekar
Join Date: Mar 2009
Posts: 18
Rep Power: 17 |
I am writing a UDF that involves volume fraction for Unsteady RANS simulation with cavitation model turned on.
I define a user defined memory variable and use the following snippet of code to access it. DEFINE_EXECUTE_AT_END(udf_name) { ........ /* All the definitions */ d=Get_Domain(3); /* Vapor Phase domain thread_loop_c(t,d) { begin_c_loop(c,t) { C_UDMI(c,t,1)=C_VOF(c,t); } } end_c_loop(c,t) } } (This is just to show how I access C_VOF.. I perform some other operations on it) I get the value of C_UDMI(c,t,1) as 0 everywhere when the volume fraction of phase 2 varies from 0 to 0.4. Can someone please help me on the same. Thanks |
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April 20, 2009, 16:03 |
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#2 |
New Member
Aditya Chunekar
Join Date: Mar 2009
Posts: 18
Rep Power: 17 |
I think the problem is with C_UDMI, since I can modify the values of volume fraction using C_VOF variable.
I guess the problem is def of C_UDMI for the mixture domain. Is there any way to define a C_UDMI for a phase ? |
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April 20, 2009, 16:57 |
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#3 |
New Member
Aditya Chunekar
Join Date: Mar 2009
Posts: 18
Rep Power: 17 |
I found something strange.
The initial contours of void fraction show the values in the range of 0 to 0.4 thread_loop_c(t,d) { begin_c_loop(c,t) { if(index==1) { C_UDMI(c,t,1)=C_VOF(c,t); /* >>>>> Over here C_VOF(c,t) is approx 0 C_VOF(c,t) = 1 ; /** Some arbit modification } } end_c_loop(c,t) } Now if I check out the contours of volume fraction for phase 2 it shows 1 everywhere... ! So somehow C_VOF does not get the initial data on void fraction.... Am i doing something obviuosly wrong ? pls let me know .. |
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April 21, 2009, 12:30 |
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#4 |
New Member
Join Date: Apr 2009
Posts: 4
Rep Power: 17 |
hello aditya,
i hope you are aware that there are some special multiphase macros avaialble. i am sure your required domain is not passing with get_domain. can you please try once with domain_sub_domain.... you can find more details on this in UDF manual. i hope fluent support can help you on this. |
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April 21, 2009, 14:02 |
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#5 |
New Member
Aditya Chunekar
Join Date: Mar 2009
Posts: 18
Rep Power: 17 |
Thanks,
But the fact that I am able to modify the value of volume fraction of phase 2 through the same loop means that I am passing the phase domain to the loop. Somehow the current values are not being accessed. I have contacted Fluent support.. Hope they help me on it |
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April 22, 2009, 12:42 |
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#6 |
New Member
Join Date: Apr 2009
Posts: 4
Rep Power: 17 |
i hope domain_id =3 what you have used is picked from define->phases, for vapour phase. since domain id are not necessarily sequential. if this is correct, would you mind sharing sample case with me. i can help you on that. i have tested at my end it works fine.
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April 23, 2009, 14:30 |
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#7 |
New Member
Aditya Chunekar
Join Date: Mar 2009
Posts: 18
Rep Power: 17 |
cfdpinku,
Cannot upload the file over here. Exeeds the file limit Can you please pm me your email ed ? The total size is around 4 mb Aditya |
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September 4, 2009, 07:21 |
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#8 |
New Member
asif nazir
Join Date: Aug 2009
Posts: 3
Rep Power: 17 |
hi u should go into subdomain thread then it work
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September 4, 2009, 07:22 |
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#9 |
New Member
asif nazir
Join Date: Aug 2009
Posts: 3
Rep Power: 17 |
THREAD_SUB_THREAD look this macro from the manual
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