Got unknown element in Post after adaption
 

My simulation model is axissymmetric. So I create the model in pie shape. After mesh adaption, I got the following message: --------------------------------------------- WARNING: The refiner was unable to identify the underlying CAD data for:

Surface triangle with vertices: [3605, 194, 1508]

Surface triangle with vertices: [194, 2168, 1508]

Surface triangle with vertices: [2168, 194, 3605]

Surface triangle with vertices: [3635, 233, 2418]

Surface triangle with vertices: [233, 1426, 2418]

Surface triangle with vertices: [1426, 233, 3635]

Surface triangle with vertices: [3635, 2467, 1426]

Surface triangle with vertices: [1426, 2467, 2418]

Surface triangle with vertices: [3605, 1508, 1560]

Surface triangle with vertices: [2168, 1560, 1508]

Surface triangle with vertices: [2168, 3605, 1560]

Surface triangle with vertices: [2418, 2467, 3635]

The CAD data for one or more of these vertices may be missing

from the data file.

These points are usually associated with the vertex of a

closed curve that is used to bound a surface. To eliminate

the problem split such curves in two so that no surfaces

are bounded by closed curves.

The refiner will continue but if it attempts to split any

of these faces it will be unable to project any of the newly

created vertices onto the underlying geometry. This could

affect your flow solution in this region. If it does not

split any of these faces then this message can be ignored. ------------------------------------------- When I see the result, there are two unknown element in the model. The magnitude of velocity component in x-direction is changed slightly around those elements. If I don't use mesh adaption, I won't get these elements. However I would like to use adaption. How do I fix this? Thank you very much.