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tstorm January 11, 2010 12:51

Question about UDS equations

I have a user-defined v2-f turbulence model that uses 4 transport equations, for k, e, v2, and f. For that model, I have defined source equations using DEFINE_SOURCE, and I have turned on their respective equations in the GUI (SOLVE - CONTROLS - SOLUTION.)

I have another model that uses user-defined Reynolds stresses. Those are stored as UDSs, but there are no source equations. Instead, they're defined inside of a DEFINE_ADJUST macro.

My question is this: do I have to turn on the equations in the SOLVE - CONTROLS SOLUTION window for UDS 4, 5, 6, and 7 (the user-defined Reynolds stresses)? I'm thinking that since there's no source equation for them, there's no need to turn them on in the GUI.

Thanks in advance.

tstorm January 11, 2010 14:02

I guess I should post an example.

Here's how the k equation is defined:

DEFINE_SOURCE(k_source, c, t, dS, eqn)
real source;

dS[eqn]=- C_R(c,t)*C_R(c,t)*C_MU*C_UDSI(c,t,V2)/C_UDMI(c,t,0);
source=C_UDMI(c,t,3) - C_R(c,t)*C_R(c,t)*C_MU*C_UDSI(c,t,V2)*C_UDSI(c,t,K )/C_UDMI(c,t,0);

return source;

And here's how one of the Reynolds stresses is defined:

(...other code...)
C_UDSI(c,t,R_11)= -2.0*cmu1*C_UDSI(c,t,V2)*T1*S11 + 2./3.*C_UDSI(c,t,K)
( cmu2*(S11*W11+S12*W21+S13*W31+S11*W11+S12*W21+S13* W31) - cmu3*(S11*S11+S12*S12+S13*S13-1./3.*S) );
(...other code...)

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