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constant velocity momentum source term does not show the expected value

    • Dino


      My domain is closed. All sides are walls. Unsteady 2D. The domain consists of two zones. I want to assign a constant velocity inside one of the zones (the yellow zone in the picture). DEFINE_ADJUST, works OK and showed ~0.1 m/s in -ve y direction in the yellow zone but very hard to converge. So, I wrote a source term but it doesn't reflect the correct value of velocity when I solve for a few time step. I tried Fixed Values in the Cell Zone but the solution diverge after a few iterations. The value coming from the UDF is slightly less than half the expected value of 0.1 m/s in the contours.

    • Rob
      Forum Moderator
      It's a momentum source, so it's being added to the current value in the cell. You may want to read up on the FIX cell zone condition, but note it'll be fairly difficult to converge and you need to avoid walls touching FIX zones as the wall functions conflict.
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