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help with UDSI_G

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Old   June 23, 2009, 13:26
Default help with UDSI_G
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Akour
Join Date: May 2009
Posts: 79
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hi,

Could anyone please tell me if there is a better way to calculate a user defined scalar gradient other than C_UDSI_G(c,t,i)...whenever I introduce this function my solution diverges very fast...even with residuals under 0.05! basically, I have 2 udfs, a poisson equation for voltage, and a ion transport equation. One of the sources appearing in the ion transport equation is the (gradient of the voltage*gradient of the charge...which are both UDSs)...the UDFs for the source terms are below, I read something about UDMIs maybe helping but im not quite sure how to implement these properly.please someone help!

Thanks a lot!
ak

charge sources:

DEFINE_SOURCE(spcharge_lin,c,t,dS,eqn)
{
real source,source_a,source_b;
static real kappa = .00000000882;

source_a = C_R(c,t)*kappa*C_UDSI_G(c,t,0)[0]*C_UDSI_G(c,t,1)[0];

source_b = C_R(c,t)*kappa*C_UDSI_G(c,t,0)[1]*C_UDSI_G(c,t,1)[1];

source=source_a+source_b;

dS[eqn] = 0;

return source;
}


voltage equation:

DEFINE_SOURCE(electric_source,c,t,dS,eqn)
{

dS[eqn] = 0;
return (C_R(c,t)*C_UDSI(c,t,1)/epsilon);

}


DEFINE_DIFFUSIVITY(electric_diff, c, t, i)
{
return 3.54;
}
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