[Maryam-A]

Hi
I want to add one transport equation for nanoparticle volume fraction to simulating nanofluid in microchannel .
I wrote uds include udf for source term and diffusion ,but cant run by this error
'"divergence detected in temperature"
-------------------------------------------------
To explain better I have one transport equation (UDS(0) for volume fraction) that includes diffusion and source terms.
source term is :
d/dx(DT*dT/dx)+d/dy(DT*dT/dy)+d/dz(DT*dT/dz)
I wanted to return sum of gradients so I calculated them in Define_Adjust. -----------------------------------------------
begin_c_loop(c,t)
{
C_UDSI(c,t,A1)=D_T*C_T_G(c,t)[0];
C_UDSI(c,t,A2)=D_T*C_T_G(c,t)[1];
C_UDSI(c,t,A3)=D_T*C_T_G(c,t)[2];
C_UDMI(c,t,A4)=C_UDSI_G(c,t,A1)[0]+
+C_UDSI_G(c,t,A2)[1]+C_UDSI_G(c,t,A3)[2];
}
end_c_loop(c,t)

}


-----------------------------------------------
DEFINE_SOURCE(alpha_source,c,t,ds,eqn)
{
real source;
source=C_UDMI(c,t,A4);
return source;
}
------------------------------------------
Actually I used UDS(A1-A3) for calculating gradients to return it as source term, but my property(viscosity and thermal conductivity) is dependent both of phi(volume fraction) and temperature,too.
So I think momentum and energy equations cant be solved before transport equation and they all should be solved simultaneously. this makes a problem for source term, I cant solve it.
------------------------------------------
I used SIMPLEC algorithm, QUICK scheme for convection-energy, Second order for UDSI(0)
----------------------------------------
I changed UDF FACTORS but cant run again
I will appreciate if you can give me more advice.

[Maryam-A]

According to my friend's advice I used UDMI for storing gradients and use it in source term, but still at start of one iteration gradients not calculated so
" fatal signal" returns.
I used EXECUTE_AT_END and "divergence detected temperature" returns!

As I said before all equation are solve together, so gradients of temperature which used in source term are unknown? maybe this sounds problem!
I'm so confused and need help