Some guidance is needed about UDF macros

highhopes · July 2, 2012, 06:06

Dear Fluent users,

I need some guidance about basic UDF macros. I am calling it basic because many of these are only seen as arguments of some macros.
My curiosity arose from a need to define boundary condition for temperature using the macro BOUNDARY_SECONDARY_GRADIENT_SOURCE(source,n,dphi,d x,A_by_es,k). The example that inspired me was written for user defined scalars which goes like this: BOUNDARY_SECONDARY_GRADIENT_SOURCE(beta0, SV_UDSI_G(phi1),dG, es, A_by_es, gamma). Here, the macro I am curious about is SV_UDSI_G(phi1). I cannot figure what it is for or what it does. I cannot find any description either.
It seems that I need to use a macro of this sort to compute temperature or do a workaround but I think I cannot do further progress without detailed information about fluent macros. So any piece of advice or instruction about this issue is appreciated. Thanks to everyone in advance.

flotus1 · July 3, 2012, 04:20

Lets see if I understood correctly:
You just want to read the temperature at cells or faces to use it in a UDF?

In this case, use

real T = F_T(f,t); //for face values
real T = C_T(c,t); //for cell values

If I got your wrong, just let me know.

highhopes · July 3, 2012, 10:41

Thank you for your response. However my purpose is not only to define a Dirichlet condition. What I am trying to do is to define the derivative of temperature at the boundary. Connectivity macros are recommended for this purpose. I could not find any explanation about SV_UDSI_G(phi1) or C_STORAGE_R_NV(c0,t0,n) that I found again in the definition of BOUNDARY_SECONDARY_GRADIENT_SOURCE.

July 2, 2012, 06:06	Some guidance is needed about UDF macros	#1
highhopes Member Join Date: Feb 2011 Posts: 62 Rep Power: 15	Dear Fluent users, I need some guidance about basic UDF macros. I am calling it basic because many of these are only seen as arguments of some macros. My curiosity arose from a need to define boundary condition for temperature using the macro BOUNDARY_SECONDARY_GRADIENT_SOURCE(source,n,dphi,d x,A_by_es,k). The example that inspired me was written for user defined scalars which goes like this: BOUNDARY_SECONDARY_GRADIENT_SOURCE(beta0, SV_UDSI_G(phi1),dG, es, A_by_es, gamma). Here, the macro I am curious about is SV_UDSI_G(phi1). I cannot figure what it is for or what it does. I cannot find any description either. It seems that I need to use a macro of this sort to compute temperature or do a workaround but I think I cannot do further progress without detailed information about fluent macros. So any piece of advice or instruction about this issue is appreciated. Thanks to everyone in advance.

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July 3, 2012, 04:20		#2
flotus1 Super Moderator Alex Join Date: Jun 2012 Location: Germany Posts: 3,427 Rep Power: 49	Lets see if I understood correctly: You just want to read the temperature at cells or faces to use it in a UDF? In this case, use real T = F_T(f,t); //for face values real T = C_T(c,t); //for cell values If I got your wrong, just let me know.

July 3, 2012, 10:41		#3
highhopes Member Join Date: Feb 2011 Posts: 62 Rep Power: 15	Thank you for your response. However my purpose is not only to define a Dirichlet condition. What I am trying to do is to define the derivative of temperature at the boundary. Connectivity macros are recommended for this purpose. I could not find any explanation about SV_UDSI_G(phi1) or C_STORAGE_R_NV(c0,t0,n) that I found again in the definition of BOUNDARY_SECONDARY_GRADIENT_SOURCE.