hi. im still doing this: hi, i am simulating the heat transfer of a fluid in a pipe. but i have problems how to define the boundaries. i have meshed the walls and the fluid and i defined the walls as "solids" and the liquid as "fluid" in gambit (my 2D modell looks like three rectangles on above each other)

now i have to define the boundaries in gambit. i define an inlet and oultlet, the outer wall lining as "wall", but i was told to define the inner line of each wall (where there is the interface between wall and fluid) as "interface". i did that but the fluent gives me following warning: WARNING: Unassigned interface zone detected for interface 7 WARNING: Unassigned interface zone detected for interface 8

how can i fix that?

thank you

Marco,

Hi, According to what I have understood from your explanation is that your trying to solve the problem as a conjugate heat transfer problem.i.e u want to solve for both solid and fluid.

In Gambit when u set fluid and solid boundaries. Following Boundary conditions has to be set for the line dividing the fluid and solid.

1. Define the line(fluid boundary side) as interface 1.

(This is the line facing the inner wall)

2. Define the line(solid bondary side) as interface 2.

(this is the line (inner wall) facing the fluid)

3. In Fluent, Go to Define > Grid Interface

Select INTERFACE 1 and INTERFACE 2.

Select COUPLED option under Interface Type.

Then click on CREATE.

Now according to me you should not have any problem.

All the Best Naveen

thanks for your help. i already tried that, but i get an error message thats says it is not ok that the one interface belongs to a solid, the otehr to a fluid zone. waht am i doing wrong?

Marco,

Can you mail me the mesh file.

Naveen

i solved the problem with the fluent support hotline. i had to define the inner wall as "wall" and just dram the half of the pipe in gambit and then set it up as rotational symetric in fluent. now it works. thanks you so far. marco