CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLUENT (
-   -   Initialization using DEFINE_INIT (

shashank312 February 13, 2012 22:07

Initialization using DEFINE_INIT
I have a fluid zone and a solid zone in my model. These two zones are connected via a wall. Fluent creates a shadow for the wall when I import the meshed model into it, where shadow faces the fluid zone and the primary wall faces the solid zone.

Now I initialize my velocity and temperature using UDF in solid (only temperature) and fluid zones. But how do I initialize the wall temperature? Can I loop over faces of a thread in a DEFINE-INIT macro?



xrs333 February 14, 2012 01:40

Variables are stored on cell zones, interior face zones, including coupled wall, do no need predefined conditions.

shashank312 February 14, 2012 01:52

But the issue is that when I plot "temperature-vs-x" on top wall and its shadow (with node values toggled on), I get three curves. One accessing the value of cell above the wall (in the solid), one using the value of cell below the wall (in the fluid) and the third on between the two (probably on the surface, not sure about this). All I know is that the third one is coming from the corners of the top wall or its shadow.

Could you understand what I just said?

xrs333 February 14, 2012 02:01

The third one you mentioned is face value and is obtained via interpolation.

shashank312 February 14, 2012 02:07

Agreed. But what to do if the values are wrong?

My temp profile in solid: Twall + ax + bf(z)

My temp profile in fluid: Twall + ax + cg(z)

My supposed/true temp profile of wall: Twall + ax. But the values of Twall are way off! Maybe because Fluent uses the c0 and c1 values to calculate the values at the centroid of the faces. Right?

shashank312 February 14, 2012 02:08

FYI: Twall, a, b, c are all constants.

All times are GMT -4. The time now is 14:50.