[Isar.charmchi]

Hi, I would like to mesh the intersection of a curved surface with a straight line in the attached image. Would you please let me know how can I do it?

[Gert-Jan]

Do I see and angle of 0°? -> Not possible.

[Isar.charmchi]

Would you please explain what do you mean of angle of 0?

Originally Posted by Gert-Jan

Do I see and angle of 0°? -> Not possible.

[Nawaf_Ar]

I believe he means a tangential face.
A reverse type of tangential case is fine, but this type, as far as I know is not possible.
Since the distance between the two faces approaches 0, but doesn't reach it. Sort of like lim x -> 0.
It is infinitesimally small. There is no cells size small enough to accommodate that 0 volume if that makes sense.

Short answer: Not possible, "Clean" your geometry. i.e eat away from it, turn these surfaces into small 90 degree intersections. Like adding a "collar" to it. The smaller the more true to life your results would be, but the finer your mesh would have to be.

[Isar.charmchi]

Thank you Nawaf for you answer. when I try to make finer mesh the quality decreases so it makes sense. The solution that you propose is similar to the car simulation, I always wonder why their mesh are like this. I mesh it with coarse mesh in that region which you can find below Do you think it is fine enough for flow simulation? my turbulence number is 1e5 order so it is quite turbulence but I am not interested in near wall behavior. However to capture the temperature in that region I have to make it finer with the solution that you proposed. Am I correct?

Originally Posted by Nawaf_Ar

I believe he means a tangential face.
A reverse type of tangential case is fine, but this type, as far as I know is not possible.
Since the distance between the two faces approaches 0, but doesn't reach it. Sort of like lim x -> 0.
It is infinitesimally small. There is no cells size small enough to accommodate that 0 volume if that makes sense.

Short answer: Not possible, "Clean" your geometry. i.e eat away from it, turn these surfaces into small 90 degree intersections. Like adding a "collar" to it. The smaller the more true to life your results would be, but the finer your mesh would have to be.

[Gert-Jan]

It depends on what question you are trying to answer when doing CFD. If you want to know the details of the flow and variables in the small gap, then you should focus on the mesh as well and add a tiny round to capture the details.
If not, then mesh as you do now. But then it is even better to fill the gap. This will save elements and potential bad angles/aspect ratios.

[Isar.charmchi]

Thanks Gert. At this stage I am not interested in that region. Later I am going to simulate the temperature in the wall so I will do this in the next step.