Hello I want to learn the basic of controlling the faces and cell threads for my udf's. Please help me in this area. kethireddy

Hello I want to learn the basic of controlling the faces and cell threads for my udf's (especially boundries). Please help me in this area. kethireddy

The best place to start is to read the UDF manual that comes with Fluent 6.

Hi Andrew Garrard, thasnks for reply.Infact i have studied the manual but there is something lacking in it. U please see the next thread in which u know my actual situation. Please see it..! I hope u can definately help out thanks a lot kethireddy

I appologise if this seem like an obvious comment,but have you turned on the UDS in fluent using Define -> User defined -> Scalers... Appart from that, have you tried running the UDF as it gives in the example 4.3.12:

where the denominator can be determined by averaging the adjacent cell's density values C_R(F_C0(f,t),F_C0_THREAD(f,t)) and C_R(F_C1(f,t),F_C1_THREAD(f,t)).

Hi thanks for ur double quick reply. i am trying to solve a transport equation using user defined scalar.In this equation i want to customorise the differential transport equation by using userdefined function so that fluent always calculates for uds instead of flux.

AS YOU SAID I TRIED earlier TO DO AVERAGING ALSO ,UNFORTUNATELY there is some segmentation error. So to make life simplere i used simple function and i have taken the F_R(f,t) , which can never be out of range of memory which is responsible for segmentation error. if i take rho as constant fluent program is giving results as expected.

please try to explain me exactly about checking the boundry thread and also accesing next faces in x dir and y direction. see u bye kethireddy