Fluctuating force graph

Using SimScale Fluid Flow / CFD
1

Hi Simscale Forum,

I am choosing a mesh for this CAD model, but all the meshes produced fluctuating force graph as shown, even at 1000s:

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I am particularly interested in forces in the X and Y direction (lift and drag). Can anyone advise me on what changes should I make to improve the covergence? any help is appreciated.

2

Hey @000xwh,

I have some suggestions that could possibly help with your convergence issues.

  1. I recommend always turning on Potential Flow Initialization
    image

  2. Its better to have a larger bounding box in order to remove potential problems with flow fluctuations. A good estimate is always a minimum of 10 X your geometry size. Yours seems a little too close to the velocity inlet, maybe add 2-3 meters in this direciton.

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  3. I would also add the estimated (or measured in CAD) center of gravity / center axis of rotation coordinates for this geometry as this could help the result control to have a stable point to measure about

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Let me know if you have any more problems

Dan

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