[swtbkim]

Hi all.

I'm simulating fan inside the cylindrical casing. There are a lot of holes at the surface of casing, and air flows through those holes.
So I would like to make cylindrical contour of velocity.
Aim is to calculate mass flow rate from inside to outside, and from outside to inside.(I think that they should be same to each other in order to satisfy conservation of mass)

This is the problem.
As you know, if you make a plane passing through solid(cylindrical casing in here), then CFD POST makes a plane excluding the solid part automatically.

But when I made cylindrical plane using surface of revolution, solid part was not excluded and even velocity contour was drawn over there.


How can it happen??
What should I do to fix this problem?


Thank you in advance.

[singer1812]

Yeah, I just tested that and got the same behavior you did.

I am not sure the logic of how they map the results onto a surface of revolution.

I thought about using inside() function to get a 1 or 0 on the surface and then using USER SURFACE based on contour to generate a new surface that only exists in the domain. But inside is PRE only. Perhaps you can think of an idea similar to this to obtain the same results.

[swtbkim]

Thanks a lot for your reply.

My strategy is similar.
1) generate a surface(surface of revolution)
2) draw contour on it,
3) make user surface based on contour
4) calculate massflow on user surface

I'm not good at CFX and CEL, and I don't understand about inside() function.
Can you explain it in details??

Thank you!

[singer1812]

inside()@subdomain is not accessible in Post. In Pre you can use it get a value that is 1 in the subdomain and 0 elsewhere.

I use it alot to generate intial values that are location specific. It is pretty handy.

[swtbkim]

I did quick searching, but I couldn't find tutorial or guide about it.
Do you have any materials about it?

I understand that you are saying, Specify the domain manually using inside() function.
But I don't know how to do...