[noodleluvmay]

Hello,

Might be a simple question, but would there be any ways to change the surfaces that are defined as inlet or outlet after all steps of meshing (snappyHexMesh)?

As far as I understand, blockMesh is where you define the boundary conditions to the faces of a domain (inlet, outlet, walls... etc).

So far I have defined inlet as left face of a box domain, outlet as right side face of the domain, and have flow normal to the inlet face.

But now because I would like to change the direction of inlet airflow, coming into the flow domain at a slight angle from top left, so I would have to change inlet to left & top faces; outlet to right & bottom faces.

When I command to run blockMesh again, it seems to clear mesh and just leave a blockMesh at the end so that I would have to run snappyHexMesh again (which takes a while for multiple cases), so I was wondering if there's any ways to bypass this?

Would really appreciate your help!
Thanks!
Nian

[HPE]

You can manually change boundary types in constant/polyMesh/boundary file.

[noodleluvmay]

Originally Posted by HPE

You can manually change boundary types in constant/polyMesh/boundary file.

Hi HPE,

Thank you for the reply! I have indeed checked the 'boundary' file in polymesh, which currently looks something like this, and I am wanting to basically make "upperWall" inlet, and "lowerWall" outlet:

6
(
    frontAndBack
    {
        type            patch;
        nFaces          21434;
        startFace       4626665;
    }
    inlet
    {
        type            patch;
        nFaces          20;
        startFace       4648099;
    }
    outlet
    {
        type            patch;
        nFaces          20;
        startFace       4648119;
    }
    lowerWall
    {
        type            wall;
        inGroups        1(wall);
        nFaces          44;
        startFace       4648139;
    }
    upperWall
    {
        type            patch;
        nFaces          44;
        startFace       4648183;
    }
    surface0
    {
        type            wall;
        inGroups        
2
(
airfoilGroup
wall
)
;
        nFaces          78336;
        startFace       4648227;
    }
)

I might not be understanding you fully in terms of "changing the boundary type", would it make sense for me to change the above to below by making "lowerWall" & "upperWall" both type "patch", and rename both of them to "inlet" and "outlet"?

6
(
    frontAndBack
    {
        type            patch;
        nFaces          21434;
        startFace       4626665;
    }
    inlet
    {
        type            patch;
        nFaces          20;
        startFace       4648099;
    }
    outlet
    {
        type            patch;
        nFaces          20;
        startFace       4648119;
    }
    outlet
    {
        type            patch;
        //inGroups        1(wall);
        nFaces          44;
        startFace       4648139;
    }
    inlet
    {
        type            patch;
        nFaces          44;
        startFace       4648183;
    }
    surface0
    {
        type            wall;
        inGroups        
2
(
airfoilGroup
wall
)
;
        nFaces          78336;
        startFace       4648227;
    }
)

Thanks again for your help!
Nian

[HPE]

Please don't touch `constant/polyMesh`. That is the place you set the main boundary types, but not boundary conditions.

Simply, you need to create `field` files, like `U`, under `0` directory. You can modify the boundary conditions thereat.