deriviation enthalpy
 

Hi, I would like adding source in energy eguation. My source is S = (j/Cp)*(dh/dx), where Cp is specific heat, dh/dx is derivation enthalpy, j is current density. How introduce derivation enthalpy to Fluent. When I writing in my udf derivation enthalpy is C_H_G(c,t) [I set: Keep temporary solver memory from being freed? [yes] ] fluent received fatal signal (ACCESS_VIOLATION)... How activate derivation enthalpy in Fluent???

Please help me!!! Best regards Tomik.