## Fluids

#### Leakage airflow

• JohannLaur
Subscriber

Hey everybody,

I want to solve a leakage airflow with Ansys Fluent. I saw the tutorial CFD ANSYS Tutorial - Pipe leakage analysis through porous soil | Fluent from Raef Kobeissi.

I also used a porous zone and connected the pipe with the porous zone with an interface. My problem is that the velocity profile is cut at the interface (see pic.). I do not understand why this happens and how i can fix it.

And the second problem is (I think it is caused by the interface) that the velocity is too huge behind the leakage. And also the pressure is too small in this area.

Do you have any ideas?

Sincerely yours,

Johannes

• klu
Ansys Employee

Hello Johannes,

Is the mesh at interface fully conformal or non-conformal please?

• Karthik R

Hello,

Could you please elaborate a little more on your geometry and the modeling approach? Could you please describe your boundary conditions? Perhaps use a sketch to describe your problem? Also, please comment on the parameters you have used in your model (velocity in the pipe, permeability of soil and so on).

Thank you.

Best Regards,

Karthik

• JohannLaur
Subscriber

Hi klu,

the mesh ist non-comformal. How can I get it conformal?

I have a pipe with a circular leakage. The leakage is far off the inlet so the flow at the inlet ist nor disturbed. Around the pipe is a box (porouse). The box is 5 to 6 times bigger than the diameter of the pipe.

My boundary conditions are: inlet: pressure inlet 8e5 Pa

outlet: pressure outlet 1e5 Pa

walls: no slip

initial cond.: p=8e5 Pa, v=0 ms^(-1), T=273,15K

I use the k-epsilon equation to solve the problem.

This is a sketch. I use the Van der Waals equation for the density (Soave-Redlich-Kwong).

Thanks a lot.

• Rob
Ansys Employee

To create a conformal mesh you need to create a multibody part in DesignModeler or use Share Topology in SpaceClaim.  Click on the help in either product and (in R19) you'll get the full online documentation which covers the process.

You may also want to split out a region downstream of the hole to increase the mesh resolution or there's mesh adaption in the solver.