CFD Online Discussion Forums - Flow field around a rotor

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Flow field around a rotor

Hi everyone.

I wish to simulate a rotor with NACA0012 blades with 8 deg AOA and 0 deg cyclic pitch. The diameter is 0.78m. I used MRF with ggi interface between static and rotating interface. The freestream velocity is 15m/s in the positive X direction.

I am getting a very low-velocity zone at the end of the blade to ggi interface of the rotor. It seems there is a strong demarkation across ggi interface in the flowfield of U. I am sharing the the filed of U, p and rho.

(The figures in XZ plane are taken at Y=-0.2m)

Can anyone please give some insight to it.
Thank you

Hi,

I had similar issues when I forgot to add the AMI/ggi to the list of nonRotatingPatches in MRFProperties. So that might be the issue?

Regards,
Tom

Thanks a lot for your reply. I just wanted to ask that should I add both ggi patches connected to rotor and stator in the list of nonRotatingPatches.

My boundary file is:

Code:

4

(

    RotorGGI

    {

        type            ggi;

        nFaces          20200;

        startFace       14221862;

        rotationAxis    (0 0 1);

        nCopies         30;

        shadowPatch     StatorGGI;

        zone            RotorGGI_faces; 

        bridgeOverlap     true;

    }

    wall

    {

        type            wall;

        nFaces          107940;

        startFace       14242062;

    }

    farfield

    {

        type            patch;

        nFaces          4800;

        startFace       14350002;

    }

    StatorGGI

    {

        type            ggi;

        nFaces          6100;

        startFace       14354802;

        rotationAxis    (0 0 1);

        nCopies         30;

        shadowPatch     RotorGGI;

        zone            StatorGGI_faces; 

        bridgeOverlap     true;

    }

)

And my MRFZones file is (presently modified as you suugested):

Code:

1

(

    cellRegion0//rotor

    {

        // Fixed patches (by default they 'move' with the MRF zone)

        nonRotatingPatches (farfield);

        nonRotatingPatches (RotorGGI);

        nonRotatingPatches (StatorGGI);

         origin    origin [0 1 0 0 0 0 0]  (0 0 0);

        axis      axis   [0 0 0 0 0 0 0]  (0 0 -1);

        omega     omega  [0 0 -1 0 0 0 0] 333.3;

    }

)

Is it correct to add both RotorGGI and StatorGGI to nonRotatingPatches or I should only add StatorGGI.

Thank you.

I apologies for asking a foolish question. I just added StatorGGI, I thinking it it working.

Thank you.

Hi,

I guess you have only the cellRegion0 as rotating cellZone? You only need to add the ggi patches that are in the rotating cellZone. I do not know if that is the StatorGGI or the RotorGGI, it depends on how you named them.

Regards,
Tom