[suiger]

the multicomponent flow includes four species. Mass diffusivity of the species is dependent of spatial coordinate. the udf as follows can be incorporated successfully. but a error "Divergence detected in AMG solver: species-0“ is displayed after I press "calculate" button. the udf is as follows.

#include "udf.h"

DEFINE_DIFFUSIVITY(myudf,c,t,i)
{
real xc[ND_ND];
real diff;
C_CENTROID(xc,c,t);
if(i==0)
{ if(xc[0]>=-0.014&&xc[0]<=-0.006&&xc[1]>=-0.140&&xc[1]<=0.140&&xc[2]>=-0.140&&xc[2]<=0.140)
diff=1.24e-11/80.34;
else
diff=5.88e-6 ;
}

else if(i==1)
{
if(xc[0]>=-0.014&&xc[0]<=-0.006&&xc[1]>=-0.140&&xc[1]<=0.140&&xc[2]>=-0.140&&xc[2]<=0.140)
diff=1.85e-11/57.05;
else
diff=5.88e-6 ;

}
else if(i==2)
{
if(xc[0]>=-0.014&&xc[0]<=-0.006&&xc[1]>=-0.140&&xc[1]<=0.140&&xc[2]>=-0.140&&xc[2]<=0.140)
diff=6.00e-11/28.68;
else
diff=5.88e-6 ;
}
return diff;
}

Can anybody help me on this please?

regards

[rewol]

Hi,

At first glance, shouldn't there be a fourth elseif(i==3), since the mixture is composed of 4 species ?

Also the error you get may not be related to your UDF, but to a large source/sink term for species. I found the link below regarding to the same error u get.

Divergence Detected in AMG solver- Species 0

Regards.

[suiger]

Firstly thank you very much! secondly,The problem was solved,u r right that the error was not related to the udf.
thank u ver much!

[rewol]

Hi, i am glad everything worked out well.

Can you please share how you solved the problem ? It can be of help / guidance to everybody out there as well.

Regards.

[AKHIL123]

could you please tell how you solved the problem