August 29, 2018 at 3:29 pm
August 29, 2018 at 6:54 pmDrAmineAnsys Employee
Search in the Fluent customization for the macro DEFINE_PROPERTY and create the expression for the viscosity,
August 30, 2018 at 12:29 amkluAnsys Employee
Add to abenhadj, the macro to access cell temperature is C_T(c,t).
August 30, 2018 at 5:41 amseeta guntiAnsys Employee
You can refer Fluent Customization documentation under "Detailed Examples". In that, DEFINE_PROPERTY macro is explained with an example of a variable viscosity profile to simulate the solidification. You can try the similar UDF with dynamic viscosity profile. Hope this help you.
August 30, 2018 at 7:07 amDevank12Subscriber
real temp = C_T(cell, thread);
mu =2.414*e-05* double pow(double 10, double 248/T-140);
i have developed a UDF for dynamic viscosity . i dnot know which is correct. if any correction plz inform me
August 30, 2018 at 7:23 amNowneshAnsys Employee
In DEFINE_PROPERTY (cell_viscosity,c,t), and real temp = C_T(cell, thread);... c,t and cell & thread names should be consistent.
August 30, 2018 at 8:18 amDrAmineAnsys Employee
real mu = 1e-5;
real fac = 1.0;
fac = 248.0/(C_T(c,t)-140.0);
mu =2.414*exp(-0.5)*pow(10.0, fac);
C_UDMI(c,t,0) = mu;
Please check the customization manal and attend a UDF Training.
May 10, 2019 at 8:52 amdsub5Subscriber
hello everyone. i have to create udf for dynamic viscosity and thermal conductivity coefficient. but have no idea about codes.
here is the formulas. if anyone can help me, i wii be glad.
August 17, 2019 at 11:37 amziadkoussaSubscriber
i am running the same udf you posted as i need the same values however after i interpret the udf and change the viscosity to user defined, when i try to initialise and calculate i get an error message saying "f1 process could not be started" and fluent automatically closes.
August 19, 2019 at 5:06 amDrAmineAnsys EmployeeTry to compile.
August 19, 2019 at 8:53 amziadkoussaSubscriber
thank you for your help.
Is there anything i need to change in the code to compile? (I am still new to ansys)
August 19, 2019 at 9:34 amDrAmineAnsys Employee
You need to install a compiler. Check in the forum for several Compiler threads. In your case your using the UDF I Posted I guess. Please check if you have defined a User Memory in Fluent.
September 27, 2019 at 10:58 amEirene2015Subscriber
Wrong help provided by abenhadj,
made me go through a whole day learning how to compile the UDFs, but the issue is the fact that his syntax is wrong.
C_UDMI(c,t,0) is not defined yet, so you cannot allocate values to it, thus the user receives a segmentation fault error!
This UDF does not require compilation. A simple interpret will work as long as the issue of C_UDMI(c,t,0) is omitted.
Do not wast time in compiling this code as I did!
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