CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLUENT (
-   -   UDF Hooks (

Sam May 16, 2002 06:44

UDF Hooks
Dear all,

I am using User-Definded Funtion Hooks(UDFH) as my k-e boundary conditions are changing with the inlet velocity condition.

I have set "initialization function" as inlet velocity, However the results were same as not using this UDF Hooks.

Can anyone tell me what this UDFH actually does?



Keil May 17, 2002 02:59

Re: UDF Hooks

You don't need to use "initialization function"(DEFINE_ININT) and DEFINE_PROFILE function should be used.

This function "DEFINE_INIT" is used when all solutions are initialized(i.e. At an initial iteration ).


Sam May 17, 2002 04:11

Re: UDF Hooks
Thanks Keil.

I still don't fully understand. Maybe I need to explain my case a bit more. I have 3 inlet condition for a Jet using k-e model. (A) inlet Velocity(e.g changes with time u= u(t))

(B) k (e.g changes with the inlet velocity= const*A^1.5)

(C) e (e.g changes with k = const*B^2)

after calculating A then B and C.

My intention was to update the condition B&C based on condition A as the TIME varies like inlet velocity.

Do I still need to use DEFINE_PROFILE? and when the initialization function in GUI, do I need to include DEFINE_INNT in the C code?

P.S If it's possible I would like to send you an e-mail with my C code. my e-mail is

Keil May 17, 2002 08:11

Re: UDF Hooks
Yes, it's O.K you can do it.

The combination of DEFINE_PROFILE and DEFINE_INIT is good for your problem.

You have to specify the initial value of K and E in DEFINE_INIT function and specify the time-dependent values in DEFINE_PROFILE function

All times are GMT -4. The time now is 12:55.