questions about udf

Lobby.H

Hi everyone

The model i'm solving has a souce term in N-S formula and this source term concerns an user defined scaler n which is decided by equation below: dn/dt=-div( n(U+Vc) + Di* div.*n ) 'cause i can't find the sign for partial differential, dn/dt was used instead. U is velocity vector, Vc is a constant and Di is the diffusivity constant. i wrote a define_source udf for N-S formula and an uds_unsteady, an uds_flux, an diffusivity for the equation above.

question 1: will the 4 udfs above be enough? what other udfs should i employ? i.e. define_adjust or something?

question 2: How can i initiate scaler n? use define_init or just set in panel?

question 3: i've set the boundary conditions as walls. will these b.c. work with n? or should i employ define_profile?

question 4: the udf for diffusivity i set will return a constant. but i wanna know will it be calculated in uds? will it be wrongly calculated in N-S?

Thanks in advance. These problems already troubled me for some days.