# Brinkman term in UDF ?

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 December 4, 2013, 03:45 Brinkman term in UDF ? #1 Member   Join Date: Oct 2013 Location: Malaysia Posts: 39 Rep Power: 11 Dear all, I could like to add for Brinkman term(second velocity derivative) in momentum sink since Darcy and Forchheimer term exist in Fluent porous setup. This Brinkman term is shown as below: mu(dynamic viscosity of fluid)*∇^2 *V (velocity vector) /ep(porosity) = ((d^2*u/(dx)^2+d^2*u/(dy)^2+d^2*u/(dz)^2)+ (d^2*v/(dx)^2+d^2*v/(dy)^2+d^2*v/(dz)^2)+ (d^2*w/(dx)^2+d^2*w/(dy)^2+d^2*w/(dz)^2))*mu(dynamic viscosity of fluid)/ep(porosity) Below is my coding for UDF: #include"udf.h" #define ep =0.93 DEFINE_SOURCE(xmom_source,c,t,dS,eqn) { real source; real x; x=C_MU_L(c,t)*(C_DUDX(c,t)+C_DUDY(c,t)+C_DUDZ(c,t) )/ep; C_UDSI(c,t,0)=x; source=C_UDSI_G(c,t); dS[eqn]=0; return source; } DEFINE_SOURCE(ymom_source,c,t,dS,eqn) { real source; real y; y=C_MU_L(c,t)*(C_DVDX(c,t)+C_DVDY(c,t)+C_DVDZ(c,t) )/ep; C_UDSI(c,t,1)=y; source=C_UDSI_G(c,t); dS[eqn]=0; return source; } DEFINE_SOURCE(zmom_source,c,t,dS,eqn) { real source; real z; z=C_MU_L(c,t)*(C_DWDX(c,t)+C_DWDY(c,t)+C_DWDZ(c,t) )/ep; C_UDSI(c,t,2)=y; source=C_UDSI_G(c,t); dS[eqn]=0; } or I need to use C_U_G(c,t) to replace C_DVDX(c,t)+C_DVDY(c,t)+C_DVDZ(c,t)? Can anyone help me to verify my attempt ? Thank you. shahab1994 likes this.

 August 8, 2014, 02:41 Brinkman term in UDF #2 New Member   Prakash Join Date: Dec 2013 Posts: 1 Rep Power: 0 u got answer for it?

 August 8, 2014, 09:52 #3 Member   Join Date: Oct 2013 Location: Malaysia Posts: 39 Rep Power: 11 Dude, I still have not solve the problem.