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Why my UDF return Zero?

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Old   August 27, 2015, 04:40
Default Why my UDF return Zero?
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Hello Friends,
I am going to calculate the following expression in FLUENT to plot the vorticity in my 2D model.

I write the following UDF:


Domain *domain;
cell_t c;
Thread *t;
thread_loop_c (t,domain)
begin_c_loop (c,t)
C_UDMI(c,t,0) = pow((C_DUDX(c,t)+C_DVDY(c,t)),2)+4*(C_DUDX(c,t)*C_ DVDY(c,t)-C_DUDY(c,t)*C_DVDX(c,t));
end_c_loop (c,t)


But when I run the execution on demand, it returns zero, that means this code is not working?
I change the formula and write C_UDMI(c,t,0) = C_DUDX(c,t) and again it returns zero. Why velocity derivatives are not working?
Thank you in advance for your assistance
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Old   August 27, 2015, 06:16
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Bruno Machado
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Add this line before your message and compute manually the values to make sure you are reading them correctly:

if((c%10000) == 0)
Message("DUDX %f, DVDY %f, DUDY%f, DVDX %f\n", C_DUDX(c,t), C_DVDY(c,t), C_DUDY(c,t), C_DVDX(c,t));
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