CFD Online Discussion Forums - Outlet behaves like solid wall

Hello,

earlier this year, I started using OpenFOAM at work. Now, I reached the point, where I need assistance.

Currently, I got stuck with the correct definition of my problem's outlet boundary conditions.

My test case has the following setup:

axis-symmetric case (see 1-geom.png):
- chamber (D = 25 mm) with small high-pressure/temperature region,
- filter,
- surrounding area
initial conditions (see 2-initial-p.png and 2-initial-T.png):
- air
- p0 = 1e+05 Pa
- T0 = 300 K
- chamber (high temperature/pressure region)
  - air
  - p_region = 20e+05 Pa
  - T_region = 1600 K
- filter (Darcy-Forchheimer)

outlet patches
- front,
- right
solver
- rhoPimpleFoam

Currently, my outlet patches seem to behave like solid walls. This understanding comes from the observation of a reflection from the front-patch (see 3-U.png and 4-U.png). However, that is not what I want. Actually, the outlet patch should be perfectly permeable and, therefore, only cut away everything from the environment, which I do not want to simulate.

Unfortunately, I could not find the solution myself (RAS-tutorials, foamInfo, etc.). Please, take a look at my outlet boundary conditions; can you find an obvious failure?

Code:

alphat:





"(front|right)"// outlet

  {type            calculated;



value           uniform 0;



}

Code:

 k:





 "(front|right)"// outlet

 {type            inletOutlet;

inletValue      uniform 1e-5;

value           uniform 1e-5;

}

Code:

 nut:





 "(front|right)"// outlet

 {type            calculated;

value           uniform 0;

}

Code:

omega:





 "(front|right)"// outlet

  {type            inletOutlet;

value           uniform 1;

inletValue      uniform 1;

}

Code:

p:





 "(front|right)"// outlet

  {type            fixedValue;

value           uniform 1e+5;

}

Code:

T:



 "(front|right)"// outlet

  {type            inletOutlet;

value           uniform 300;

inletValue      uniform 300;

}

Code:

 U:





 "(front|right)"// outlet

  {type            pressureInletOutletVelocity;

value           uniform (0 0 0);

inletValue      uniform (0 0 0);



}

Let me know if I need to provide some additional information.

Harald