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Turbulent Dispersion Model (Burns et al)

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Old   June 6, 2021, 11:54
Question Turbulent Dispersion Model (Burns et al)
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Is my UDF for Burns et al model right or wrong ?

# include "udf.h"
DEFINE_VECTOR_EXCHANGE_PROPERTY(burnetal,cell,mixt ure,liquid,solid,Ftdvector)
{
Thread *thread_l, *thread_s;
real rho_l,rho_s,Sigmapq,alpha_l,alpha_s,term,Ftd,Ctd,K pq;
real px,py,pz,sx,sy,sz;
thread_l=THREAD_SUB_THREAD(mixture,liquid);
thread_s=THREAD_SUB_THREAD(mixture,solid);
/* Calculation of Gradients */
alpha_l=C_VOF(cell, thread_l); /* liquid phase volume fraction */
alpha_s=C_VOF(cell, thread_s); /* Solid Phase Volume fraction */
rho_l=C_R(cell,thread_l);
rho_s=C_R(cell,thread_s);
Kpq=alpha_l*rho_l*C_K(cell, thread_l)+alpha_s*rho_s*C_K(cell, thread_s);
Ctd=1;
Sigmapq=.9;
term=Ctd*Kpq*C_MU_T(cell,thread_l)/(rho_l*Sigmapq);
px=C_VOF_G(cell,thread_l)[0]/alpha_l;
py=C_VOF_G(cell,thread_l)[1]/alpha_l;
pz=C_VOF_G(cell,thread_l)[2]/alpha_l;
sx=C_VOF_G(cell,thread_s)[0]/alpha_s;
sy=C_VOF_G(cell,thread_s)[1]/alpha_s;
sz=C_VOF_G(cell,thread_s)[2]/alpha_s;
/* Calculation of the Final Expression */
Ftdvector[0]=term*(px-sx);
Ftdvector[1]=term*(py-sy);
Ftdvector[2]=term*(pz-sz);
printf("\n%f\t%f\t%f\t%f\t%f\t%f\t%f\t%f\t%f\t%f\t %f\t%f\t%f\t%f\t%f\t%f\t%f\t",Ftdvector[0],Ftdvector[1],Ftdvector[2],Ctd,term,px,py,pz,sx,sy,sz,alpha_l,alpha_s,Kpq,C_ MU_T(cell,thread_l),C_K(cell, thread_l),C_K(cell, thread_s));
}

Last edited by Prantik Das; June 7, 2021 at 00:24.
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Old   June 7, 2021, 03:16
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Alexander
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Code:
# include "udf.h"
DEFINE_VECTOR_EXCHANGE_PROPERTY(burnetal,cell,mixture,liquid,solid,Ftdvector)
{
Thread *thread_l, *thread_s;
real rho_l,rho_s,Sigmapq,alpha_l,alpha_s,term,Ftd,Ctd,K,pq;
real px,py,pz,sx,sy,sz,Kpq;
thread_l=THREAD_SUB_THREAD(mixture,liquid);
thread_s=THREAD_SUB_THREAD(mixture,solid);
/* Calculation of Gradients */
alpha_l=C_VOF(cell, thread_l); /* liquid phase volume fraction */
alpha_s=C_VOF(cell, thread_s); /* Solid Phase Volume fraction */
rho_l=C_R(cell,thread_l);
rho_s=C_R(cell,thread_s);
Kpq=alpha_l*rho_l*C_K(cell, thread_l)+alpha_s*rho_s*C_K(cell, thread_s);
Ctd=1;
Sigmapq=.9;
term=Ctd*Kpq*C_MU_T(cell,thread_l)/(rho_l*Sigmapq);
px=C_VOF_G(cell,thread_l)[0]/alpha_l;
py=C_VOF_G(cell,thread_l)[1]/alpha_l;
pz=C_VOF_G(cell,thread_l)[2]/alpha_l;
sx=C_VOF_G(cell,thread_s)[0]/alpha_s;
sy=C_VOF_G(cell,thread_s)[1]/alpha_s;
sz=C_VOF_G(cell,thread_s)[2]/alpha_s;
/* Calculation of the Final Expression */
Ftdvector[0]=term*(px-sx);
Ftdvector[1]=term*(py-sy);
Ftdvector[2]=term*(pz-sz);
Message0("\n%f\t%f\t%f\t%f\t%f\t%f\t%f\t%f\t%f\t%f\t %f\t%f\t%f\t%f\t%f\t%f\t%f\t",Ftdvector[0],Ftdvector[1],Ftdvector[2],Ctd,term,px,py,pz,sx,sy,sz,alpha_l,alpha_s,Kpq,C_MU_T(cell,thread_l),C_K(cell, thread_l),C_K(cell, thread_s));
}
compile
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Old   June 7, 2021, 09:30
Question Floating Point Exception
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Getting Error at Node 0: floating point exception error.

Divergence detected in AMG solver: pressure correction Stabilizing k to enhance linear solver robustness.
Stabilizing epsilon to enhance linear solver robustness.
Stabilizing vof-1 to enhance linear solver robustness.

Divergence detected in AMG solver: vof-1
Error at host: floating point exception

Error at Node 0: floating point exception

Error: floating point exception
Error Object: #f

while using this UDF
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Old   June 7, 2021, 19:49
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you are printing most variables into console, check their values.
if the values are wrong, fix it
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Old   June 8, 2021, 01:17
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In general: a UDF is correct if I it does what you want. So if you want to know if it is correct: try it. If it works, be happy, if it does not, fix it.

I don't understand the tendency to put code on a forum and ask other people if it is correct... Just try it!

And if, like in your case, you get errors: mention that!
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"The UDF library you are trying to load (libudf) is not compiled for parallel use on the current platform" is NOT the error after compiling. It is the error after loading. To see compiler errors, look at your screen after you click "build".
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